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| /linux/arch/riscv/kernel/ |
| H A D | return_address.c | 680341382da56bd192ebfa4e58eaf4fec2e5bca7 Fri Feb 02 02:51:02 CET 2024 Zong Li <zong.li@sifive.com> riscv: add CALLER_ADDRx support
CALLER_ADDRx returns caller's address at specified level, they are used
for several tracers. These macros eventually use
__builtin_return_address(n) to get the caller's address if arch doesn't
define their own implementation.
In RISC-V, __builtin_return_address(n) only works when n == 0, we need
to walk the stack frame to get the caller's address at specified level.
data.level started from 'level + 3' due to the call flow of getting
caller's address in RISC-V implementation. If we don't have additional
three iteration, the level is corresponding to follows:
callsite -> return_address -> arch_stack_walk -> walk_stackframe
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level 3 level 2 level 1 level 0
Fixes: 10626c32e382 ("riscv/ftrace: Add basic support")
Cc: stable@vger.kernel.org
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Zong Li <zong.li@sifive.com>
Link: https://lore.kernel.org/r/20240202015102.26251-1-zong.li@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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| H A D | Makefile | diff 680341382da56bd192ebfa4e58eaf4fec2e5bca7 Fri Feb 02 02:51:02 CET 2024 Zong Li <zong.li@sifive.com> riscv: add CALLER_ADDRx support
CALLER_ADDRx returns caller's address at specified level, they are used
for several tracers. These macros eventually use
__builtin_return_address(n) to get the caller's address if arch doesn't
define their own implementation.
In RISC-V, __builtin_return_address(n) only works when n == 0, we need
to walk the stack frame to get the caller's address at specified level.
data.level started from 'level + 3' due to the call flow of getting
caller's address in RISC-V implementation. If we don't have additional
three iteration, the level is corresponding to follows:
callsite -> return_address -> arch_stack_walk -> walk_stackframe
| | | |
level 3 level 2 level 1 level 0
Fixes: 10626c32e382 ("riscv/ftrace: Add basic support")
Cc: stable@vger.kernel.org
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Zong Li <zong.li@sifive.com>
Link: https://lore.kernel.org/r/20240202015102.26251-1-zong.li@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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