- 04 4月, 2015 1 次提交
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由 Borislav Petkov 提交于
Quentin caught a corner case with the generation of instruction padding in the ALTERNATIVE_2 macro: if len(orig_insn) < len(alt1) < len(alt2), then not enough padding gets added and that is not good(tm) as we could overwrite the beginning of the next instruction. Luckily, at the time of this writing, we don't have ALTERNATIVE_2() invocations which have that problem and even if we did, a simple fix would be to prepend the instructions with enough prefixes so that that corner case doesn't happen. However, best it would be if we fixed it properly. See below for a simple, abstracted example of what we're doing. So what we ended up doing is, we compute the max(len(alt1), len(alt2)) - len(orig_insn) and feed that value to the .skip gas directive. The max() cannot have conditionals due to gas limitations, thus the fancy integer math. With this patch, all ALTERNATIVE_2 sites get padded correctly; generating obscure test cases pass too: #define alt_max_short(a, b) ((a) ^ (((a) ^ (b)) & -(-((a) < (b))))) #define gen_skip(orig, alt1, alt2, marker) \ .skip -((alt_max_short(alt1, alt2) - (orig)) > 0) * \ (alt_max_short(alt1, alt2) - (orig)),marker .pushsection .text, "ax" .globl main main: gen_skip(1, 2, 4, 0x09) gen_skip(4, 1, 2, 0x10) ... .popsection Thanks to Quentin for catching it and double-checking the fix! Reported-by: NQuentin Casasnovas <quentin.casasnovas@oracle.com> Signed-off-by: NBorislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150404133443.GE21152@pd.tnicSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 03 4月, 2015 8 次提交
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由 Borislav Petkov 提交于
... instead of a naked number, for better readability. Signed-off-by: NBorislav Petkov <bp@suse.de> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1428054130-25847-1-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Borislav Petkov 提交于
Commit: d56fe4bf ("x86/asm/entry/64: Always set up SYSENTER MSRs") missed to add "ULL" to the 0 and wrmsrl_safe() complains: arch/x86/kernel/cpu/common.c: In function ‘syscall_init’: arch/x86/kernel/cpu/common.c:1226:2: warning: right shift count >= width of type wrmsrl_safe(MSR_IA32_SYSENTER_CS, 0); Fix it. Signed-off-by: NBorislav Petkov <bp@suse.de> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1428054130-25847-1-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Borislav Petkov 提交于
Commit: e2b32e67 ("x86, kaslr: randomize module base load address") made module base address randomization unconditional and didn't regard disabled KKASLR due to CONFIG_HIBERNATION and command line option "nokaslr". For more info see (now reverted) commit: f47233c2 ("x86/mm/ASLR: Propagate base load address calculation") In order to propagate KASLR status to kernel proper, we need a single bit in boot_params.hdr.loadflags and we've chosen bit 1 thus leaving the top-down allocated bits for bits supposed to be used by the bootloader. Originally-From: Jiri Kosina <jkosina@suse.cz> Suggested-by: NH. Peter Anvin <hpa@zytor.com> Signed-off-by: NBorislav Petkov <bp@suse.de> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Borislav Petkov 提交于
Commit: 4214a16b ("x86/asm/entry/64/compat: Use SYSRETL to return from compat mode SYSENTER") removed the last user of ENABLE_INTERRUPTS_SYSEXIT32. Kill the macro now too. Signed-off-by: NBorislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: virtualization@lists.linux-foundation.org Link: http://lkml.kernel.org/r/1428049714-829-1-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
SYSEXIT is scary on 64-bit kernels -- SYSEXIT must be invoked with usergs and IRQs on. That means that we rely on STI to correctly mask interrupts for one instruction. This is okay by itself, but the semantics with respect to NMIs are unclear. Avoid the whole issue by using SYSRETL instead. For background, Intel CPUs don't allow SYSCALL from compat mode, but they do allow SYSRETL back to compat mode. Go figure. To avoid doing too much at once, this doesn't revamp the calling convention. We still return with EBP, EDX, and ECX on the user stack. Oddly this seems to be 30 cycles or so faster. Avoiding POPFQ and STI will account for under half of that, I think, so my best guess is that Intel just optimizes SYSRET much better than SYSEXIT. Signed-off-by: NAndy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/57a0bf1b5230b2716a64ebe48e9bc1110f7ab433.1428019097.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
We write a stack pointer to MSR_IA32_SYSENTER_ESP exactly once, and we unnecessarily cache the value in tss.sp1. We never read the cached value. Remove all of the caching. It serves no purpose. Suggested-by: NDenys Vlasenko <dvlasenk@redhat.com> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/05a0163eb33ef5208363f0015496855da7cebadd.1428002830.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
At Denys' request, clean up the comment describing stack padding in the 32-bit sysenter path. No code changes. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/41fee7bb8490ae840fe7ef2699f9c2feb932e729.1428002830.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Ross Zwisler 提交于
Add support for the new CLWB (cache line write back) instruction. This instruction was announced in the document "Intel Architecture Instruction Set Extensions Programming Reference" with reference number 319433-022. https://software.intel.com/sites/default/files/managed/0d/53/319433-022.pdf The CLWB instruction is used to write back the contents of dirtied cache lines to memory without evicting the cache lines from the processor's cache hierarchy. This should be used in favor of clflushopt or clflush in cases where you require the cache line to be written to memory but plan to access the data again in the near future. One of the main use cases for this is with persistent memory where CLWB can be used with PCOMMIT to ensure that data has been accepted to memory and is durable on the DIMM. This function shows how to properly use CLWB/CLFLUSHOPT/CLFLUSH and PCOMMIT with appropriate fencing: void flush_and_commit_buffer(void *vaddr, unsigned int size) { void *vend = vaddr + size - 1; for (; vaddr < vend; vaddr += boot_cpu_data.x86_clflush_size) clwb(vaddr); /* Flush any possible final partial cacheline */ clwb(vend); /* * Use SFENCE to order CLWB/CLFLUSHOPT/CLFLUSH cache flushes. * (MFENCE via mb() also works) */ wmb(); /* PCOMMIT and the required SFENCE for ordering */ pcommit_sfence(); } After this function completes the data pointed to by vaddr is has been accepted to memory and will be durable if the vaddr points to persistent memory. Regarding the details of how the alternatives assembly is set up, we need one additional byte at the beginning of the CLFLUSH so that we can flip it into a CLFLUSHOPT by changing that byte into a 0x66 prefix. Two options are to either insert a 1 byte ASM_NOP1, or to add a 1 byte NOP_DS_PREFIX. Both have no functional effect with the plain CLFLUSH, but I've been told that executing a CLFLUSH + prefix should be faster than executing a CLFLUSH + NOP. We had to hard code the assembly for CLWB because, lacking the ability to assemble the CLWB instruction itself, the next closest thing is to have an xsaveopt instruction with a 0x66 prefix. Unfortunately XSAVEOPT itself is also relatively new, and isn't included by all the GCC versions that the kernel needs to support. Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Acked-by: NBorislav Petkov <bp@suse.de> Acked-by: NH. Peter Anvin <hpa@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1422377631-8986-3-git-send-email-ross.zwisler@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 02 4月, 2015 3 次提交
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由 Boris Ostrovsky 提交于
Some of x86 bare-metal and Xen CPU initialization code is common between the two and therefore can be factored out to avoid code duplication. As a side effect, doing so will also extend the fix provided by commit a7fcf28d ("x86/asm/entry: Replace this_cpu_sp0() with current_top_of_stack() to x86_32") to 32-bit Xen PV guests. Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: NDavid Vrabel <david.vrabel@citrix.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: konrad.wilk@oracle.com Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1427897534-5086-1-git-send-email-boris.ostrovsky@oracle.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
__BOOT_TSS = (GDT_ENTRY_BOOT_TSS * 8) GDT_ENTRY_BOOT_TSS = (GDT_ENTRY_BOOT_CS + 2) GDT_ENTRY_BOOT_CS = 2 (2 + 2) * 8 = 4 * 8 = 32 = 0x20 No code changes. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Reviewed-by: NSteven Rostedt <rostedt@goodmis.org> Acked-by: NBorislav Petkov <bp@suse.de> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427899858-7165-2-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
No code changes. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Acked-by: NBorislav Petkov <bp@suse.de> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427899858-7165-1-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 01 4月, 2015 7 次提交
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由 Denys Vlasenko 提交于
Logically, we just want to jump around the following instruction and its prologue/epilogue: call *sys_call_table(,%rax,8) if the syscall number is too big - we do not specifically target the "int_ret_from_sys_call" label. Use a local, numerical label for this jump, for more clarity. This also makes the code smaller: -ffffffff8187756b: 0f 87 0f 00 00 00 ja ffffffff81877580 <int_ret_from_sys_call> +ffffffff8187756b: 77 0f ja ffffffff8187757c <int_ret_from_sys_call> because jumps to global labels are never translated to short jump instructions by GAS. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427821211-25099-9-git-send-email-dvlasenk@redhat.com [ Improved the changelog. ] Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
There is no reason to use MOVQ to load a non-negative immediate constant value into a 64-bit register. MOVL does the same, since the upper 32 bits are zero-extended by the CPU. This makes the code a bit smaller, while leaving functionality unchanged. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427821211-25099-8-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
At the 'exit_intr' label we test whether interrupt/exception was in kernel. If it did, we jump to the preemption check. If preemption does happen (IOW if we call preempt_schedule_irq()), we go back to 'exit_intr'. But it's pointless, we already know that the test succeeded last time, preemption doesn't change the fact that interrupt/exception was in the kernel. We can go back directly to checking PER_CPU_VAR(__preempt_count) instead. This makes the 'exit_intr' label unused, drop it. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427821211-25099-5-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
At this location, we already have interrupts off, always. To be more specific, we already disabled them here: ret_from_intr: DISABLE_INTERRUPTS(CLBR_NONE) Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427821211-25099-4-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
Get rid of #define obfuscation of retint_kernel in CONFIG_PREEMPT case by defining retint_kernel label always, not only for CONFIG_PREEMPT. Strip retint_kernel of .global-ness (ENTRY macro) - it has no users outside of this file. This looks like cosmetics, but it is not: "je LABEL" can be optimized to short jump by assember only if LABEL is not global, for global labels jump is always a near one with relocation. Convert retint_restore_args to a local numeric label, making it clearer that it is not used elsewhere in the file. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427821211-25099-3-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
This mimics the recent similar 64-bit change. Saves ~110 bytes of code. Patch was run-tested on 32 and 64 bits, Intel and AMD CPU. I also looked at the diff of entry_64.o disassembly, to have a different view of the changes. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427821211-25099-2-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
SYSRET code path has a small irq-off block. On this code path, TRACE_IRQS_ON can't be called right before interrupts are enabled for real, we can't clobber registers there. So current code does it earlier, in a safe place. But with this, TRACE_IRQS_OFF/ON frames just two fast instructions, which is ridiculous: now most of irq-off block is _outside_ of the framing. Do the same thing that we do on SYSCALL entry: do not track this irq-off block, it is very small to ever cause noticeable irq latency. Be careful: make sure that "jnz int_ret_from_sys_call_irqs_off" now does invoke TRACE_IRQS_OFF - move int_ret_from_sys_call_irqs_off label before TRACE_IRQS_OFF. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427821211-25099-1-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 31 3月, 2015 3 次提交
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由 Ingo Molnar 提交于
user_mode_ignore_vm86() can be used instead of user_mode(), in places where we have already done a v8086_mode() security check of ptregs. But doing this check in the wrong place would be a bug that could result in security problems, and also the naming still isn't very clear. Furthermore, it only affects 32-bit kernels, while most development happens on 64-bit kernels. If we replace them with user_mode() checks then the cost is only a very minor increase in various slowpaths: text data bss dec hex filename 10573391 703562 1753042 13029995 c6d26b vmlinux.o.before 10573423 703562 1753042 13030027 c6d28b vmlinux.o.after So lets get rid of this distinction once and for all. Acked-by: NBorislav Petkov <bp@suse.de> Acked-by: NAndy Lutomirski <luto@kernel.org> Cc: Andrew Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brad Spengler <spender@grsecurity.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150329090233.GA1963@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
At exit_intr, we GET_THREAD_INFO(%rcx) and then jump to retint_kernel if saved CS was from kernel. But the code at retint_kernel doesn't need %rcx. Move GET_THREAD_INFO(%rcx) down, after CS check and branch. While at it, remove "has a correct top of stack" comment. After recent changes which eliminated FIXUP_TOP_OF_STACK, we always have a correct pt_regs layout. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427738975-7391-5-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
The "retint_kernel" code block is misplaced. Since its logical continuation is "retint_restore_args", it is more natural to place it above that label. This also makes two jumps "short". This change only moves code block around, without changing logic. This enables the next simplification: making "retint_restore_args" label a local numeric one. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427738975-7391-2-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 27 3月, 2015 9 次提交
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由 Denys Vlasenko 提交于
There are a couple of syscall argument zero-extension instructions in the 32-bit compat entry code, and it was mentioned that people keep trying to optimize them out, introducing bugs. Make them more visible, and add a "do not remove" comment. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427452582-21624-3-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
The existing comment has proven to be not very clear. Replace it with a comment similar to the one we now have in the 64-bit syscall entry point. (Three instances, one per 32-bit syscall entry). In the INT80 entry point's CFI annotations, replace mysterious expressions with numric constants. In this case, raw numbers look more understandable. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427452582-21624-2-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
This is a missing bit of the recent MOV-to-PUSH conversion. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427452582-21624-1-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
The comment is ancient, it dates to the time when only AMD's x86_64 implementation existed. AMD wasn't (and still isn't) supporting SYSENTER, so these writes were "just in case" back then. This has changed: Intel's x86_64 appeared, and Intel does support SYSENTER in long mode. "Some future 64-bit CPU" is here already. The code may appear "buggy" for AMD as it stands, since MSR_IA32_SYSENTER_EIP is only 32-bit for AMD CPUs. Writing a kernel function's address to it would drop high bits. Subsequent use of this MSR for branch via SYSENTER seem to allow user to transition to CPL0 while executing his code. Scary, eh? Explain why that is not a bug: because SYSENTER insn would not work on AMD CPU. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427453956-21931-1-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
Internally, lockdep_sys_exit_thunk saves callee-clobbered registers, and calls a C function, lockdep_sys_exit. Thus, callee-preserved registers won't be mangled, there is no need to save them. Patch was run-tested. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427314468-12763-4-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
There is no need to have an extra level of macro indirection here. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427314468-12763-3-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
This change simply moves defines around (even if it's not obvious in a patch form). Nothing is changed. This is a preparation for folding ARCH_LOCKDEP_SYS_EXIT defines into their users. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427314468-12763-2-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
The $AUDIT_ARCH_X86_64 parameter to syscall_trace_enter_phase1/2 is a 32-bit constant, loading it with 32-bit MOV produces 5-byte insn instead of 10-byte MOVABS one. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427303896-24023-3-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
A named label "ret_from_sys_call" implies that there are jumps to this location from elsewhere, as happens with many other labels in this file. But this label is used only by the JMP a few insns above. To make that obvious, use local numeric label instead. Improve comments: "and return regs->ax" isn't too informative. We always return regs->ax. The comment suggesting that it'd be cool to use rip relative addressing for CALL is deleted. It's unclear why that would be an improvement - we aren't striving to use position-independent code here. PIC code here would require something like LEA sys_call_table(%rip),reg + CALL *(reg,%rax*8)... "iret frame is also incomplete" is no longer true, fix that too. Also fix typo in comment. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1427303896-24023-1-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 25 3月, 2015 9 次提交
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由 Ingo Molnar 提交于
Conflicts: arch/x86/kernel/entry_64.S Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Ingo Molnar 提交于
- extend/clarify explanations where necessary - move comments from macro values to before the macro, to make them more consistent, and to reduce preprocessor overhead - sort GDT index and selector values likewise by number - use consistent, modern kernel coding style across the file - capitalize consistently - use consistent vertical spacing - remove the unused get_limit() method (noticed by Andy Lutomirski) No change in code (verified with objdump -d): 64-bit defconfig+kvmconfig: 815a129bc1f80de6445c1d8ca5b97cad vmlinux.o.before.asm 815a129bc1f80de6445c1d8ca5b97cad vmlinux.o.after.asm 32-bit defconfig+kvmconfig: e659ef045159ddf41a0771b33a34aae5 vmlinux.o.before.asm e659ef045159ddf41a0771b33a34aae5 vmlinux.o.after.asm Acked-by: NAndy Lutomirski <luto@amacapital.net> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
We currently have a race: if we're preempted during syscall exit, we can fail to process syscall return work that is queued up while we're preempted in ret_from_sys_call after checking ti.flags. Fix it by disabling interrupts before checking ti.flags. Reported-by: NStefan Seyfried <stefan.seyfried@googlemail.com> Reported-by: NTakashi Iwai <tiwai@suse.de> Signed-off-by: NAndy Lutomirski <luto@kernel.org> Acked-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Tejun Heo <tj@kernel.org> Fixes: 96b6352c ("x86_64, entry: Remove the syscall exit audit") Link: http://lkml.kernel.org/r/189320d42b4d671df78c10555976bb10af1ffc75.1427137498.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Ingo Molnar 提交于
The THREAD_INFO() macro has a somewhat confusingly generic name, defined in a generic .h C header file. It also does not make it clear that it constructs a memory operand for use in assembly code. Rename it to ASM_THREAD_INFO() to make it all glaringly obvious on first glance. Acked-by: NBorislav Petkov <bp@suse.de> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/20150324184442.GC14760@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Ingo Molnar 提交于
Before: TI_sysenter_return+THREAD_INFO(%rsp,3*8),%r10d After: movl THREAD_INFO(TI_sysenter_return, %rsp, 3*8), %r10d to turn it into a clear thread_info accessor. No code changed: md5: fb4cb2b3ce05d89940ca304efc8ff183 ia32entry.o.before.asm fb4cb2b3ce05d89940ca304efc8ff183 ia32entry.o.after.asm e39f2958a5d1300158e276e4f7663263 entry_64.o.before.asm e39f2958a5d1300158e276e4f7663263 entry_64.o.after.asm Acked-by: NAndy Lutomirski <luto@kernel.org> Acked-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/20150324184411.GB14760@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Ingo Molnar 提交于
Explain the background, and add a real example. Acked-by: NDenys Vlasenko <dvlasenk@redhat.com> Acked-by: NAndy Lutomirski <luto@kernel.org> Acked-by: NBorislav Petkov <bp@suse.de> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/20150324184311.GA14760@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Ingo Molnar 提交于
On CONFIG_IA32_EMULATION=y kernels we set up MSR_IA32_SYSENTER_CS/ESP/EIP, but on !CONFIG_IA32_EMULATION kernels we leave them unchanged. Clear them to make sure the instruction is disabled properly. SYSCALL is set up properly in both cases. Acked-by: NDenys Vlasenko <dvlasenk@redhat.com> Acked-by: NAndy Lutomirski <luto@amacapital.net> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
This file just defines a number of constants, and a few macros and inline functions. It is particularly badly written. For example, it is not trivial to see how descriptors are numbered (you'd expect that should be easy, right?). This change deobfuscates it via the following changes: Group all GDT_ENTRY_foo together (move intervening stuff away). Number them explicitly: use a number, not PREV_DEFINE+1, +2, +3: I want to immediately see that GDT_ENTRY_PNPBIOS_CS32 is 18. Seeing (GDT_ENTRY_KERNEL_BASE+6) instead is not useful. The above change allows to remove GDT_ENTRY_KERNEL_BASE and GDT_ENTRY_PNPBIOS_BASE, which weren't used anywhere else. After a group of GDT_ENTRY_foo, define all selector values. Remove or improve some comments. In particular: Comment deleted as stating the obvious: /* * The GDT has 32 entries */ #define GDT_ENTRIES 32 "The segment offset needs to contain a RPL. Grr. -AK" changed to "Selectors need to also have a correct RPL (+3 thingy)" "GDT layout to get 64bit syscall right (sysret hardcodes gdt offsets)" expanded into a description *how exactly* sysret hardcodes them. Patch was tested to compile and not change vmlinux.o on 32-bit and 64-bit builds (verified with objdump). Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
With the FIXUP_TOP_OF_STACK macro removed, this intermediate jump is unnecessary. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Acked-by: NBorislav Petkov <bp@suse.de> Acked-by: NAndy Lutomirski <luto@kernel.org> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1426785469-15125-5-git-send-email-dvlasenk@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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