- 07 3月, 2015 2 次提交
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由 Andy Lutomirski 提交于
I broke 32-bit kernels. The implementation of sp0 was correct as far as I can tell, but sp0 was much weirder on x86_32 than I realized. It has the following issues: - Init's sp0 is inconsistent with everything else's: non-init tasks are offset by 8 bytes. (I have no idea why, and the comment is unhelpful.) - vm86 does crazy things to sp0. Fix it up by replacing this_cpu_sp0() with current_top_of_stack() and using a new percpu variable to track the top of the stack on x86_32. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> 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> Fixes: 75182b16 ("x86/asm/entry: Switch all C consumers of kernel_stack to this_cpu_sp0()") Link: http://lkml.kernel.org/r/d09dbe270883433776e0cbee3c7079433349e96d.1425692936.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
The change: 75182b16 ("x86/asm/entry: Switch all C consumers of kernel_stack to this_cpu_sp0()") had the unintended side effect of changing the return value of current_thread_info() during part of the context switch process. Change it back. This has no effect as far as I can tell -- it's just for consistency. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> 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/9fcaa47dd8487db59eed7a3911b6ae409476763e.1425692936.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 06 3月, 2015 6 次提交
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由 Andy Lutomirski 提交于
This has nothing to do with the init thread or the initial anything. It's just the CPU's TSS. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> 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/a0bd5e26b32a2e1f08ff99017d0997118fbb2485.1425611534.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
The INIT_TSS is unnecessary. Just define the initial TSS where 'cpu_tss' is defined. While we're at it, merge the 32-bit and 64-bit definitions. The only syntactic change is that 32-bit kernels were computing sp0 as long, but now they compute it as unsigned long. Verified by objdump: the contents and relocations of .data..percpu..shared_aligned are unchanged on 32-bit and 64-bit kernels. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> 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/8fc39fa3f6c5d635e93afbdd1a0fe0678a6d7913.1425611534.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
It has nothing to do with init -- there's only one TSS per cpu. Other names considered include: - current_tss: Confusing because we never switch the tss. - singleton_tss: Too long. This patch was generated with 's/init_tss/cpu_tss/g'. Followup patches will fix INIT_TSS and INIT_TSS_IST by hand. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> 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/da29fb2a793e4f649d93ce2d1ed320ebe8516262.1425611534.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
The ia32 sysenter code loaded the top of the kernel stack into rsp by loading kernel_stack and then adjusting it. It can be simplified to just read sp0 directly. This requires the addition of a new asm-offsets entry for sp0. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> 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/88ff9006163d296a0665338585c36d9bfb85235d.1425611534.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
This will make modifying the semantics of kernel_stack easier. The change to ist_begin_non_atomic() is necessary because sp0 no longer points to the same THREAD_SIZE-aligned region as RSP; it's one byte too high for that. At Denys' suggestion, rather than offsetting it, just check explicitly that we're in the correct range ending at sp0. This has the added benefit that we no longer assume that the thread stack is aligned to THREAD_SIZE. Suggested-by: NDenys Vlasenko <dvlasenk@redhat.com> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> 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/ef8254ad414cbb8034c9a56396eeb24f5dd5b0de.1425611534.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
We currently store references to the top of the kernel stack in multiple places: kernel_stack (with an offset) and init_tss.x86_tss.sp0 (no offset). The latter is defined by hardware and is a clean canonical way to find the top of the stack. Add an accessor so we can start using it. This needs minor paravirt tweaks. On native, sp0 defines the top of the kernel stack and is therefore always correct. On Xen and lguest, the hypervisor tracks the top of the stack, but we want to start reading sp0 in the kernel. Fixing this is simple: just update our local copy of sp0 as well as the hypervisor's copy on task switches. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/8d675581859712bee09a055ed8f785d80dac1eca.1425611534.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 05 3月, 2015 14 次提交
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由 Wang Nan 提交于
As early_trap_init() doesn't use IST, replace set_intr_gate_ist() and set_system_intr_gate_ist() with their standard counterparts. set_intr_gate() requires a trace_debug symbol which we don't have and won't use. This patch separates set_intr_gate() into two parts, and uses base version in early_trap_init(). Reported-by: NAndy Lutomirski <luto@amacapital.net> Signed-off-by: NWang Nan <wangnan0@huawei.com> Acked-by: NAndy Lutomirski <luto@amacapital.net> Cc: <dave.hansen@linux.intel.com> Cc: <lizefan@huawei.com> Cc: <masami.hiramatsu.pt@hitachi.com> Cc: <oleg@redhat.com> Cc: <rostedt@goodmis.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1425010789-13714-1-git-send-email-wangnan0@huawei.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
'ret_from_fork' checks TIF_IA32 to determine whether 'pt_regs' and the related state make sense for 'ret_from_sys_call'. This is entirely the wrong check. TS_COMPAT would make a little more sense, but there's really no point in keeping this optimization at all. This fixes a return to the wrong user CS if we came from int 0x80 in a 64-bit task. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> 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/4710be56d76ef994ddf59087aad98c000fbab9a4.1424989793.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
Avoid redundant load of %r11 (it is already loaded a few instructions before). Also simplify %rsp restoration, instead of two steps: add $0x80, %rsp mov 0x18(%rsp), %rsp we can do a simplified single step to restore user-space RSP: mov 0x98(%rsp), %rsp and get the same result. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> [ Clarified the changelog. ] Cc: Alexei Starovoitov <ast@plumgrid.com> 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: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1aef69b346a6db0d99cdfb0f5ba83e8c985e27d7.1424989793.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
Constants such as SS+8 or SS+8-RIP are mysterious. In most cases, SS+8 is just meant to be SIZEOF_PTREGS, SS+8-RIP is RIP's offset in the iret frame. This patch changes some of these constants to be less mysterious. No code changes (verified with objdump). Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Alexei Starovoitov <ast@plumgrid.com> 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: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1d20491384773bd606e23a382fac23ddb49b5178.1424989793.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
This patch does a lot of cleanup in comments and formatting, but it does not change any code: - Rename 'save_paranoid' to 'paranoid_entry': this makes naming similar to its "non-paranoid" sibling, 'error_entry', and to its counterpart, 'paranoid_exit'. - Use the same CFI annotation atop 'paranoid_entry' and 'error_entry'. - Fix irregular indentation of assembler operands. - Add/fix comments on top of 'paranoid_entry' and 'error_entry'. - Remove stale comment about "oldrax". - Make comments about "no swapgs" flag in ebx more prominent. - Deindent wrongly indented top-level comment atop 'paranoid_exit'. - Indent wrongly deindented comment inside 'error_entry'. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Alexei Starovoitov <ast@plumgrid.com> 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/4640f9fcd5ea46eb299b1cd6d3f5da3167d2f78d.1424989793.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
For some odd reason, these two functions are at the very top of the file. "save_paranoid"'s caller is approximately in the middle of it, move it there. Move 'ret_from_fork' to be right after fork/exec helpers. This is a pure block move, nothing is changed in the function bodies. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Alexei Starovoitov <ast@plumgrid.com> 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: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/6446bbfe4094532623a5b83779b7015fec167a9d.1424989793.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
SYSCALL/SYSRET and SYSENTER/SYSEXIT have weird semantics. Moreover, they differ in 32- and 64-bit mode. What is saved? What is not? Is rsp set? Are interrupts disabled? People tend to not remember these details well enough. This patch adds comments which explain in detail what registers are modified by each of these instructions. The comments are placed immediately before corresponding entry and exit points. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Alexei Starovoitov <ast@plumgrid.com> 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: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/a94b98b63527797c871a81402ff5060b18fa880a.1424989793.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
Nothing references it anymore. Reported-by: NDenys Vlasenko <vda.linux@googlemail.com> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> 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> Fixes: 96b6352c ("x86_64, entry: Remove the syscall exit audit and schedule optimizations") Link: http://lkml.kernel.org/r/dd2a4d26ecc7a5db61b476727175cd99ae2b32a4.1424989793.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
ARGOFFSET is zero now, removing it changes no code. A few macros lost "offset" parameter, since it is always zero now too. No code changes - verified with objdump. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Alexei Starovoitov <ast@plumgrid.com> 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: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/8689f937622d9d2db0ab8be82331fa15e4ed4713.1424989793.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
RESTORE_EXTRA_REGS + RESTORE_C_REGS looks small, but it's a lot of instructions (fourteen). Let's reuse them. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> [ Cleaned up the labels. ] Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Alexei Starovoitov <ast@plumgrid.com> 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/1421272101-16847-2-git-send-email-dvlasenk@redhat.com Link: http://lkml.kernel.org/r/59d71848cee3ec9eb48c0252e602efd6bd560e3c.1424989793.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
- Misleading and slightly incorrect comments in "struct pt_regs" are fixed (four instances). - Fix incorrect comment atop EMPTY_FRAME macro. - Explain in more detail what we do with stack layout during hw interrupt. - Correct comments about "partial stack frame" which are no longer true. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Alexei Starovoitov <ast@plumgrid.com> 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/1423778052-21038-3-git-send-email-dvlasenk@redhat.com Link: http://lkml.kernel.org/r/e1f4429c491fe6ceeddb879dea2786e0f8920f9c.1424989793.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
The 64-bit entry code was using six stack slots less by not saving/restoring registers which are callee-preserved according to the C ABI, and was not allocating space for them. Only when syscalls needed a complete "struct pt_regs" was the complete area allocated and filled in. As an additional twist, on interrupt entry a "slightly less truncated pt_regs" trick is used, to make nested interrupt stacks easier to unwind. This proved to be a source of significant obfuscation and subtle bugs. For example, 'stub_fork' had to pop the return address, extend the struct, save registers, and push return address back. Ugly. 'ia32_ptregs_common' pops return address and "returns" via jmp insn, throwing a wrench into CPU return stack cache. This patch changes the code to always allocate a complete "struct pt_regs" on the kernel stack. The saving of registers is still done lazily. "Partial pt_regs" trick on interrupt stack is retained. Macros which manipulate "struct pt_regs" on stack are reworked: - ALLOC_PT_GPREGS_ON_STACK allocates the structure. - SAVE_C_REGS saves to it those registers which are clobbered by C code. - SAVE_EXTRA_REGS saves to it all other registers. - Corresponding RESTORE_* and REMOVE_PT_GPREGS_FROM_STACK macros reverse it. 'ia32_ptregs_common', 'stub_fork' and friends lost their ugly dance with the return pointer. LOAD_ARGS32 in ia32entry.S now uses symbolic stack offsets instead of magic numbers. 'error_entry' and 'save_paranoid' now use SAVE_C_REGS + SAVE_EXTRA_REGS instead of having it open-coded yet again. Patch was run-tested: 64-bit executables, 32-bit executables, strace works. Timing tests did not show measurable difference in 32-bit and 64-bit syscalls. Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Alexei Starovoitov <ast@plumgrid.com> 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/1423778052-21038-2-git-send-email-dvlasenk@redhat.com Link: http://lkml.kernel.org/r/b89763d354aa23e670b9bdf3a40ae320320a7c2e.1424989793.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
Since the last fix of this nature, a few more instances have crept in. Fix them up. No object code changes (constants have the same value). Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Alexei Starovoitov <ast@plumgrid.com> 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/1423778052-21038-1-git-send-email-dvlasenk@redhat.com Link: http://lkml.kernel.org/r/f5e1c4084319a42e5f14d41e2d638949ce66bc08.1424989793.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Denys Vlasenko 提交于
Sequences: pushl_cfi %reg CFI_REL_OFFSET reg, 0 and: popl_cfi %reg CFI_RESTORE reg happen quite often. This patch adds macros which generate them. No assembly changes (verified with objdump -dr vmlinux.o). Signed-off-by: NDenys Vlasenko <dvlasenk@redhat.com> Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Alexei Starovoitov <ast@plumgrid.com> 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/1421017655-25561-1-git-send-email-dvlasenk@redhat.com Link: http://lkml.kernel.org/r/2202eb90f175cf45d1b2d1c64dbb5676a8ad07ad.1424989793.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 04 3月, 2015 1 次提交
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由 Brian Gerst 提交于
Combine the 32-bit syscall tables into one file. Signed-off-by: NBrian Gerst <brgerst@gmail.com> Cc: Borislav Petkov <bp@alien8.de> 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/1425439896-8322-3-git-send-email-brgerst@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 28 2月, 2015 1 次提交
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由 Steven Rostedt 提交于
Commit: 1e02ce4c ("x86: Store a per-cpu shadow copy of CR4") added a shadow CR4 such that reads and writes that do not modify the CR4 execute much faster than always reading the register itself. The change modified cpu_init() in common.c, so that the shadow CR4 gets initialized before anything uses it. Unfortunately, there's two cpu_init()s in common.c. There's one for 64-bit and one for 32-bit. The commit only added the shadow init to the 64-bit path, but the 32-bit path needs the init too. Link: http://lkml.kernel.org/r/20150227125208.71c36402@gandalf.local.home Fixes: 1e02ce4c "x86: Store a per-cpu shadow copy of CR4" Signed-off-by: NSteven Rostedt <rostedt@goodmis.org> Acked-by: NAndy Lutomirski <luto@amacapital.net> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20150227145019.2bdd4354@gandalf.local.homeSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 26 2月, 2015 1 次提交
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由 Wang Nan 提交于
Before this patch early_trap_init() installs DEBUG_STACK for X86_TRAP_BP and X86_TRAP_DB. However, DEBUG_STACK doesn't work correctly until cpu_init() <-- trap_init(). This patch passes 0 to set_intr_gate_ist() and set_system_intr_gate_ist() instead of DEBUG_STACK to let it use same stack as kernel, and installs DEBUG_STACK for them in trap_init(). As core runs at ring 0 between early_trap_init() and trap_init(), there is no chance to get a bad stack before trap_init(). As NMI is also enabled in trap_init(), we don't need to care about is_debug_stack() and related things used in arch/x86/kernel/nmi.c. Signed-off-by: NWang Nan <wangnan0@huawei.com> Reviewed-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Acked-by: NSteven Rostedt <rostedt@goodmis.org> Cc: <dave.hansen@linux.intel.com> Cc: <lizefan@huawei.com> Cc: <luto@amacapital.net> Cc: <oleg@redhat.com> Link: http://lkml.kernel.org/r/1424929779-13174-1-git-send-email-wangnan0@huawei.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 25 2月, 2015 2 次提交
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由 Andy Lutomirski 提交于
CLONE_SETTLS is expected to write a TLS entry in the GDT for 32-bit callers and to set FSBASE for 64-bit callers. The correct check is is_ia32_task(), which returns true in the context of a 32-bit syscall. TIF_IA32 is set if the task itself has a 32-bit personality, which is not the same thing. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Link: http://lkml.kernel.org/r/45e2d0d695393d76406a0c7225b82c76223e0cc5.1424822291.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Lutomirski 提交于
The ability for modified CS and/or SS to be useful has nothing to do with TIF_IA32. Similarly, if there's an exploit involving changing CS or SS, it's exploitable with or without a TIF_IA32 check. So just delete the check. Signed-off-by: NAndy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Link: http://lkml.kernel.org/r/71c7ab36456855d11ae07edd4945a7dfe80f9915.1424822291.git.luto@amacapital.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 24 2月, 2015 1 次提交
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由 David Vrabel 提交于
Hypercalls submitted by user space tools via the privcmd driver can take a long time (potentially many 10s of seconds) if the hypercall has many sub-operations. A fully preemptible kernel may deschedule such as task in any upcall called from a hypercall continuation. However, in a kernel with voluntary or no preemption, hypercall continuations in Xen allow event handlers to be run but the task issuing the hypercall will not be descheduled until the hypercall is complete and the ioctl returns to user space. These long running tasks may also trigger the kernel's soft lockup detection. Add xen_preemptible_hcall_begin() and xen_preemptible_hcall_end() to bracket hypercalls that may be preempted. Use these in the privcmd driver. When returning from an upcall, call xen_maybe_preempt_hcall() which adds a schedule point if if the current task was within a preemptible hypercall. Since _cond_resched() can move the task to a different CPU, clear and set xen_in_preemptible_hcall around the call. Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com> Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
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- 23 2月, 2015 6 次提交
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由 Borislav Petkov 提交于
This is based on a patch originally by hpa. With the current improvements to the alternatives, we can simply use %P1 as a mem8 operand constraint and rely on the toolchain to generate the proper instruction sizes. For example, on 32-bit, where we use an empty old instruction we get: apply_alternatives: feat: 6*32+8, old: (c104648b, len: 4), repl: (c195566c, len: 4) c104648b: alt_insn: 90 90 90 90 c195566c: rpl_insn: 0f 0d 4b 5c ... apply_alternatives: feat: 6*32+8, old: (c18e09b4, len: 3), repl: (c1955948, len: 3) c18e09b4: alt_insn: 90 90 90 c1955948: rpl_insn: 0f 0d 08 ... apply_alternatives: feat: 6*32+8, old: (c1190cf9, len: 7), repl: (c1955a79, len: 7) c1190cf9: alt_insn: 90 90 90 90 90 90 90 c1955a79: rpl_insn: 0f 0d 0d a0 d4 85 c1 all with the proper padding done depending on the size of the replacement instruction the compiler generates. Signed-off-by: NBorislav Petkov <bp@suse.de> Cc: H. Peter Anvin <hpa@linux.intel.com>
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由 Borislav Petkov 提交于
Booting a 486 kernel on an AMD guest with this patch applied, says: apply_alternatives: feat: 0*32+25, old: (c160a475, len: 5), repl: (c19557d4, len: 5) c160a475: alt_insn: 68 10 35 00 c1 c19557d4: rpl_insn: 68 80 39 00 c1 which is: old insn VA: 0xc160a475, CPU feat: X86_FEATURE_XMM, size: 5 simd_coprocessor_error: c160a475: 68 10 35 00 c1 push $0xc1003510 <do_general_protection> repl insn: 0xc19557d4, size: 5 c160a475: 68 80 39 00 c1 push $0xc1003980 <do_simd_coprocessor_error> Signed-off-by: NBorislav Petkov <bp@suse.de>
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由 Borislav Petkov 提交于
Alternatives allow now for an empty old instruction. In this case we go and pad the space with NOPs at assembly time. However, there are the optimal, longer NOPs which should be used. Do that at patching time by adding alt_instr.padlen-sized NOPs at the old instruction address. Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: NBorislav Petkov <bp@suse.de>
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由 Borislav Petkov 提交于
Up until now we had to pay attention to relative JMPs in alternatives about how their relative offset gets computed so that the jump target is still correct. Or, as it is the case for near CALLs (opcode e8), we still have to go and readjust the offset at patching time. What is more, the static_cpu_has_safe() facility had to forcefully generate 5-byte JMPs since we couldn't rely on the compiler to generate properly sized ones so we had to force the longest ones. Worse than that, sometimes it would generate a replacement JMP which is longer than the original one, thus overwriting the beginning of the next instruction at patching time. So, in order to alleviate all that and make using JMPs more straight-forward we go and pad the original instruction in an alternative block with NOPs at build time, should the replacement(s) be longer. This way, alternatives users shouldn't pay special attention so that original and replacement instruction sizes are fine but the assembler would simply add padding where needed and not do anything otherwise. As a second aspect, we go and recompute JMPs at patching time so that we can try to make 5-byte JMPs into two-byte ones if possible. If not, we still have to recompute the offsets as the replacement JMP gets put far away in the .altinstr_replacement section leading to a wrong offset if copied verbatim. For example, on a locally generated kernel image old insn VA: 0xffffffff810014bd, CPU feat: X86_FEATURE_ALWAYS, size: 2 __switch_to: ffffffff810014bd: eb 21 jmp ffffffff810014e0 repl insn: size: 5 ffffffff81d0b23c: e9 b1 62 2f ff jmpq ffffffff810014f2 gets corrected to a 2-byte JMP: apply_alternatives: feat: 3*32+21, old: (ffffffff810014bd, len: 2), repl: (ffffffff81d0b23c, len: 5) alt_insn: e9 b1 62 2f ff recompute_jumps: next_rip: ffffffff81d0b241, tgt_rip: ffffffff810014f2, new_displ: 0x00000033, ret len: 2 converted to: eb 33 90 90 90 and a 5-byte JMP: old insn VA: 0xffffffff81001516, CPU feat: X86_FEATURE_ALWAYS, size: 2 __switch_to: ffffffff81001516: eb 30 jmp ffffffff81001548 repl insn: size: 5 ffffffff81d0b241: e9 10 63 2f ff jmpq ffffffff81001556 gets shortened into a two-byte one: apply_alternatives: feat: 3*32+21, old: (ffffffff81001516, len: 2), repl: (ffffffff81d0b241, len: 5) alt_insn: e9 10 63 2f ff recompute_jumps: next_rip: ffffffff81d0b246, tgt_rip: ffffffff81001556, new_displ: 0x0000003e, ret len: 2 converted to: eb 3e 90 90 90 ... and so on. This leads to a net win of around 40ish replacements * 3 bytes savings =~ 120 bytes of I$ on an AMD guest which means some savings of precious instruction cache bandwidth. The padding to the shorter 2-byte JMPs are single-byte NOPs which on smart microarchitectures means discarding NOPs at decode time and thus freeing up execution bandwidth. Signed-off-by: NBorislav Petkov <bp@suse.de>
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由 Borislav Petkov 提交于
Up until now we have always paid attention to make sure the length of the new instruction replacing the old one is at least less or equal to the length of the old instruction. If the new instruction is longer, at the time it replaces the old instruction it will overwrite the beginning of the next instruction in the kernel image and cause your pants to catch fire. So instead of having to pay attention, teach the alternatives framework to pad shorter old instructions with NOPs at buildtime - but only in the case when len(old instruction(s)) < len(new instruction(s)) and add nothing in the >= case. (In that case we do add_nops() when patching). This way the alternatives user shouldn't have to care about instruction sizes and simply use the macros. Add asm ALTERNATIVE* flavor macros too, while at it. Also, we need to save the pad length in a separate struct alt_instr member for NOP optimization and the way to do that reliably is to carry the pad length instead of trying to detect whether we're looking at single-byte NOPs or at pathological instruction offsets like e9 90 90 90 90, for example, which is a valid instruction. Thanks to Michael Matz for the great help with toolchain questions. Signed-off-by: NBorislav Petkov <bp@suse.de>
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由 Borislav Petkov 提交于
Make it pass __func__ implicitly. Also, dump info about each replacing we're doing. Fixup comments and style while at it. Signed-off-by: NBorislav Petkov <bp@suse.de>
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- 22 2月, 2015 1 次提交
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由 Yannick Guerrini 提交于
Change 'ssociative' to 'associative' Signed-off-by: NYannick Guerrini <yguerrini@tomshardware.fr> Cc: Borislav Petkov <bp@suse.de> Cc: Bryan O'Donoghue <pure.logic@nexus-software.ie> Cc: Chris Bainbridge <chris.bainbridge@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Steven Honeyman <stevenhoneyman@gmail.com> Cc: trivial@kernel.org Link: http://lkml.kernel.org/r/1424558510-1420-1-git-send-email-yguerrini@tomshardware.frSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 21 2月, 2015 2 次提交
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由 Petr Mladek 提交于
__recover_probed_insn() should always be called from an address where an instructions starts. The check for ftrace_location() might help to discover a potential inconsistency. This patch adds WARN_ON() when the inconsistency is detected. Also it adds handling of the situation when the original code can not get recovered. Suggested-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: NPetr Mladek <pmladek@suse.cz> Cc: Ananth NMavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1424441250-27146-3-git-send-email-pmladek@suse.czSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Petr Mladek 提交于
can_probe() checks if the given address points to the beginning of an instruction. It analyzes all the instructions from the beginning of the function until the given address. The code might be modified by another Kprobe. In this case, the current code is read into a buffer, int3 breakpoint is replaced by the saved opcode in the buffer, and can_probe() analyzes the buffer instead. There is a bug that __recover_probed_insn() tries to restore the original code even for Kprobes using the ftrace framework. But in this case, the opcode is not stored. See the difference between arch_prepare_kprobe() and arch_prepare_kprobe_ftrace(). The opcode is stored by arch_copy_kprobe() only from arch_prepare_kprobe(). This patch makes Kprobe to use the ideal 5-byte NOP when the code can be modified by ftrace. It is the original instruction, see ftrace_make_nop() and ftrace_nop_replace(). Note that we always need to use the NOP for ftrace locations. Kprobes do not block ftrace and the instruction might get modified at anytime. It might even be in an inconsistent state because it is modified step by step using the int3 breakpoint. The patch also fixes indentation of the touched comment. Note that I found this problem when playing with Kprobes. I did it on x86_64 with gcc-4.8.3 that supported -mfentry. I modified samples/kprobes/kprobe_example.c and added offset 5 to put the probe right after the fentry area: static struct kprobe kp = { .symbol_name = "do_fork", + .offset = 5, }; Then I was able to load kprobe_example before jprobe_example but not the other way around: $> modprobe jprobe_example $> modprobe kprobe_example modprobe: ERROR: could not insert 'kprobe_example': Invalid or incomplete multibyte or wide character It did not make much sense and debugging pointed to the bug described above. Signed-off-by: NPetr Mladek <pmladek@suse.cz> Acked-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Ananth NMavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1424441250-27146-2-git-send-email-pmladek@suse.czSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 20 2月, 2015 1 次提交
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由 Jiri Kosina 提交于
Commit f47233c2 ("x86/mm/ASLR: Propagate base load address calculation") causes PAGE_SIZE redefinition warnings for UML subarch builds. This is caused by added includes that were leftovers from previous patch versions are are not actually needed (especially page_types.h inlcude in module.c). Drop those stray includes. Reported-by: Nkbuild test robot <fengguang.wu@intel.com> Signed-off-by: NJiri Kosina <jkosina@suse.cz> Cc: Borislav Petkov <bp@suse.de> Cc: H. Peter Anvin <hpa@linux.intel.com> Cc: Kees Cook <keescook@chromium.org> Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1502201017240.28769@pobox.suse.czSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 19 2月, 2015 2 次提交
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由 Quentin Casasnovas 提交于
We do not check the input data bounds containing the microcode before copying a struct microcode_intel_header from it. A specially crafted microcode could cause the kernel to read invalid memory and lead to a denial-of-service. Signed-off-by: NQuentin Casasnovas <quentin.casasnovas@oracle.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/1422964824-22056-3-git-send-email-quentin.casasnovas@oracle.com [ Made error message differ from the next one and flipped comparison. ] Signed-off-by: NBorislav Petkov <bp@suse.de>
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由 Quentin Casasnovas 提交于
mc_saved_tmp is a static array allocated on the stack, we need to make sure mc_saved_count stays within its bounds, otherwise we're overflowing the stack in _save_mc(). A specially crafted microcode header could lead to a kernel crash or potentially kernel execution. Signed-off-by: NQuentin Casasnovas <quentin.casasnovas@oracle.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/1422964824-22056-1-git-send-email-quentin.casasnovas@oracle.comSigned-off-by: NBorislav Petkov <bp@suse.de>
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