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riscv: Fix fp alignment bug in perf_callchain_user()

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[ Upstream commit 22ab08955ea13be04a8efd20cc30890e0afaa49c ]

The standard RISC-V calling convention said:
	"The stack grows downward and the stack pointer is always
	kept 16-byte aligned".

So perf_callchain_user() should check whether 16-byte aligned for fp.

Link: https://riscv.org/wp-content/uploads/2015/01/riscv-calling.pdf

Fixes: dbeb90b0c1eb ("riscv: Add perf callchain support")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Cc: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/r/20240708032847.2998158-2-ruanjinjie@huawei.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jinjie Ruan 2024-07-08 11:28:46 +08:00 committed by Ksawlii
parent c0f95fbea9
commit 82b35b5043
1 changed files with 1 additions and 1 deletions
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2
arch/riscv/kernel/perf_callchain.c
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@ -71,7 +71,7 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
perf_callchain_store(entry, regs->epc);
fp = user_backtrace(entry, fp, regs->ra);
while (fp && !(fp & 0x3) && entry->nr < entry->max_stack)
while (fp && !(fp & 0x7) && entry->nr < entry->max_stack)
fp = user_backtrace(entry, fp, 0);
}