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powerpc/pseries: Fix hcall tracepoints with JUMP_LABEL=n
authorNicholas Piggin <npiggin@gmail.com>
Tue, 9 May 2023 09:15:59 +0000 (19:15 +1000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 13 Sep 2023 07:42:48 +0000 (09:42 +0200)
[ Upstream commit 750bd41aeaeb1f0e0128aa4f8fcd6dd759713641 ]

With JUMP_LABEL=n, hcall_tracepoint_refcount's address is being tested
instead of its value. This results in the tracing slowpath always being
taken unnecessarily.

Fixes: 9a10ccb29c0a2 ("powerpc/pseries: move hcall_tracepoint_refcount out of .toc")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230509091600.70994-1-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
arch/powerpc/platforms/pseries/hvCall.S patch | blob | history

diff --git a/arch/powerpc/platforms/pseries/hvCall.S b/arch/powerpc/platforms/pseries/hvCall.S
index 762eb15..fc50b9c 100644 (file)
--- a/arch/powerpc/platforms/pseries/hvCall.S
+++ b/arch/powerpc/platforms/pseries/hvCall.S
@@ -89,6 +89,7 @@ BEGIN_FTR_SECTION;                                            \
        b       1f;                                             \
 END_FTR_SECTION(0, 1);                                         \
        LOAD_REG_ADDR(r12, hcall_tracepoint_refcount) ;         \
+       ld      r12,0(r12);                                     \
        std     r12,32(r1);                                     \
        cmpdi   r12,0;                                          \
        bne-    LABEL;                                          \
Domain: System / Kernel;