提交 · 2bfc6cd81bd17e4306e24ee47b9554c967bcb499 · openeuler / Kernel

26 4月, 2021 11 次提交

riscv: Move kernel mapping outside of linear mapping · 2bfc6cd8

由 Alexandre Ghiti 提交于 4月 11, 2021

This is a preparatory patch for relocatable kernel and sv48 support.

The kernel used to be linked at PAGE_OFFSET address therefore we could use
the linear mapping for the kernel mapping. But the relocated kernel base
address will be different from PAGE_OFFSET and since in the linear mapping,
two different virtual addresses cannot point to the same physical address,
the kernel mapping needs to lie outside the linear mapping so that we don't
have to copy it at the same physical offset.

The kernel mapping is moved to the last 2GB of the address space, BPF
is now always after the kernel and modules use the 2GB memory range right
before the kernel, so BPF and modules regions do not overlap. KASLR
implementation will simply have to move the kernel in the last 2GB range
and just take care of leaving enough space for BPF.

In addition, by moving the kernel to the end of the address space, both
sv39 and sv48 kernels will be exactly the same without needing to be
relocated at runtime.
Suggested-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NAlexandre Ghiti <alex@ghiti.fr>
[Palmer: Squash the STRICT_RWX fix, and a !MMU fix]
Signed-off-by: NPalmer Dabbelt <palmerdabbelt@google.com>

2bfc6cd8

samples/kprobes: Add riscv support · 8a07ac39

由 Jisheng Zhang 提交于 3月 30, 2021

Add riscv specific info dump in both handler_pre() and handler_post().
Signed-off-by: NJisheng Zhang <jszhang@kernel.org>
Acked-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NPalmer Dabbelt <palmerdabbelt@google.com>

8a07ac39

riscv: Select HAVE_DYNAMIC_FTRACE when -fpatchable-function-entry is available · adebc881

由 Nathan Chancellor 提交于 3月 25, 2021

clang prior to 13.0.0 does not support -fpatchable-function-entry for
RISC-V.

clang: error: unsupported option '-fpatchable-function-entry=8' for target 'riscv64-unknown-linux-gnu'

To avoid this error, only select HAVE_DYNAMIC_FTRACE when this option is
not available.

Fixes: afc76b8b ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT")
Link: https://github.com/ClangBuiltLinux/linux/issues/1268Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NNathan Chancellor <nathan@kernel.org>
Reviewed-by: NFangrui Song <maskray@google.com>
Signed-off-by: NPalmer Dabbelt <palmerdabbelt@google.com>

adebc881

riscv: Workaround mcount name prior to clang-13 · 7ce04771

由 Nathan Chancellor 提交于 3月 25, 2021

Prior to clang 13.0.0, the RISC-V name for the mcount symbol was
"mcount", which differs from the GCC version of "_mcount", which results
in the following errors:

riscv64-linux-gnu-ld: init/main.o: in function `__traceiter_initcall_level':
main.c:(.text+0xe): undefined reference to `mcount'
riscv64-linux-gnu-ld: init/main.o: in function `__traceiter_initcall_start':
main.c:(.text+0x4e): undefined reference to `mcount'
riscv64-linux-gnu-ld: init/main.o: in function `__traceiter_initcall_finish':
main.c:(.text+0x92): undefined reference to `mcount'
riscv64-linux-gnu-ld: init/main.o: in function `.LBB32_28':
main.c:(.text+0x30c): undefined reference to `mcount'
riscv64-linux-gnu-ld: init/main.o: in function `free_initmem':
main.c:(.text+0x54c): undefined reference to `mcount'

This has been corrected in https://reviews.llvm.org/D98881 but the
minimum supported clang version is 10.0.1. To avoid build errors and to
gain a working function tracer, adjust the name of the mcount symbol for
older versions of clang in mount.S and recordmcount.pl.

Link: https://github.com/ClangBuiltLinux/linux/issues/1331Signed-off-by: NNathan Chancellor <nathan@kernel.org>
Reviewed-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NPalmer Dabbelt <palmerdabbelt@google.com>

7ce04771

scripts/recordmcount.pl: Fix RISC-V regex for clang · 2f095504

由 Nathan Chancellor 提交于 3月 25, 2021

Clang can generate R_RISCV_CALL_PLT relocations to _mcount:

$ llvm-objdump -dr build/riscv/init/main.o | rg mcount
                000000000000000e:  R_RISCV_CALL_PLT     _mcount
                000000000000004e:  R_RISCV_CALL_PLT     _mcount

After this, the __start_mcount_loc section is properly generated and
function tracing still works.

Link: https://github.com/ClangBuiltLinux/linux/issues/1331Signed-off-by: NNathan Chancellor <nathan@kernel.org>
Reviewed-by: NFangrui Song <maskray@google.com>
Signed-off-by: NPalmer Dabbelt <palmerdabbelt@google.com>

2f095504

riscv: Use $(LD) instead of $(CC) to link vDSO · 7f3d3490

由 Nathan Chancellor 提交于 3月 25, 2021

Currently, the VDSO is being linked through $(CC). This does not match
how the rest of the kernel links objects, which is through the $(LD)
variable.

When linking with clang, there are a couple of warnings about flags that
will not be used during the link:

clang-12: warning: argument unused during compilation: '-no-pie' [-Wunused-command-line-argument]
clang-12: warning: argument unused during compilation: '-pg' [-Wunused-command-line-argument]

'-no-pie' was added in commit 85602bea ("RISC-V: build vdso-dummy.o
with -no-pie") to override '-pie' getting added to the ld command from
distribution versions of GCC that enable PIE by default. It is
technically no longer needed after commit c2c81bb2 ("RISC-V: Fix the
VDSO symbol generaton for binutils-2.35+"), which removed vdso-dummy.o
in favor of generating vdso-syms.S from vdso.so with $(NM) but this also
resolves the issue in case it ever comes back due to having full control
over the $(LD) command. '-pg' is for function tracing, it is not used
during linking as clang states.

These flags could be removed/filtered to fix the warnings but it is
easier to just match the rest of the kernel and use $(LD) directly for
linking. See commits

fe00e50b ("ARM: 8858/1: vdso: use $(LD) instead of $(CC) to link VDSO")
691efbed ("arm64: vdso: use $(LD) instead of $(CC) to link VDSO")
2ff90699 ("MIPS: VDSO: Use $(LD) instead of $(CC) to link VDSO")
2b2a2584 ("s390/vdso: Use $(LD) instead of $(CC) to link vDSO")

for more information.

The flags are converted to linker flags and '--eh-frame-hdr' is added to
match what is added by GCC implicitly, which can be seen by adding '-v'
to GCC's invocation.

Additionally, since this area is being modified, use the $(OBJCOPY)
variable instead of an open coded $(CROSS_COMPILE)objcopy so that the
user's choice of objcopy binary is respected.

Link: https://github.com/ClangBuiltLinux/linux/issues/803
Link: https://github.com/ClangBuiltLinux/linux/issues/970Signed-off-by: NNathan Chancellor <nathan@kernel.org>
Reviewed-by: NFangrui Song <maskray@google.com>
Signed-off-by: NPalmer Dabbelt <palmerdabbelt@google.com>

7f3d3490

riscv: sifive: Apply errata "cip-1200" patch · bff3ff52