[PATCH v3 1/2] riscv: Fix fp alignment bug in perf_callchain_user()

[Jinjie Ruan]

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 at huawei.com>
Cc: Björn Töpel <bjorn at kernel.org>
---
 arch/riscv/kernel/perf_callchain.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/perf_callchain.c b/arch/riscv/kernel/perf_callchain.c
index 3348a61de7d9..2932791e9388 100644
--- a/arch/riscv/kernel/perf_callchain.c
+++ b/arch/riscv/kernel/perf_callchain.c
@@ -62,7 +62,7 @@ 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);
 }
 
-- 
2.34.1