riscv: stacktrace: fix backtracing through exceptions

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[ Upstream commit 51356ce60e ]

Prior to commit 5d5fc33ce5 ("riscv: Improve exception and system call
latency"), backtrace through exception worked since ra was filled with
ret_from_exception symbol address and the stacktrace code checked 'pc' to
be equal to that symbol. Now that handle_exception uses regular 'call'
instructions, this isn't working anymore and backtrace stops at
handle_exception(). Since there are multiple call site to C code in the
exception handling path, rather than checking multiple potential return
addresses, add a new symbol at the end of exception handling and check pc
to be in that range.

Fixes: 5d5fc33ce5 ("riscv: Improve exception and system call latency")
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20241209155714.1239665-1-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Clément Léger 2024-12-09 16:57:12 +01:00 • committed by Greg Kroah-Hartman

parent d2bd51954a

commit 607b8740c6

2 changed files with 4 additions and 1 deletions

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arch/riscv/kernel/entry.S

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4

arch/riscv/kernel/stacktrace.c

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