powerpc/ftrace: Pass the correct stack pointer for DYNAMIC_FTRACE_WITH_REGS

For DYNAMIC_FTRACE_WITH_REGS, we should be passing-in the original set
of registers in pt_regs, to capture the state _before_ ftrace_caller.
However, we are instead passing the stack pointer *after* allocating a
stack frame in ftrace_caller. Fix this by saving the proper value of r1
in pt_regs. Also, use SAVE_10GPRS() to simplify the code.

Fixes: 4dd4af0241d3 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI")
Cc: stable@vger.kernel.org # v4.6+
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
index 7c933a99f5d578bdfd1408b16d4e7fe33e95e4a9..fa0921410fa4c89593bf56d1a277832d80aede82 100644 (file)
--- a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
+++ b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
@@ -45,10 +45,14 @@ _GLOBAL(ftrace_caller)
        stdu    r1,-SWITCH_FRAME_SIZE(r1)
 
        /* Save all gprs to pt_regs */
-       SAVE_8GPRS(0,r1)
-       SAVE_8GPRS(8,r1)
-       SAVE_8GPRS(16,r1)
-       SAVE_8GPRS(24,r1)
+       SAVE_GPR(0, r1)
+       SAVE_10GPRS(2, r1)
+       SAVE_10GPRS(12, r1)
+       SAVE_10GPRS(22, r1)
+
+       /* Save previous stack pointer (r1) */
+       addi    r8, r1, SWITCH_FRAME_SIZE
+       std     r8, GPR1(r1)
 
        /* Load special regs for save below */
        mfmsr   r8
@@ -103,10 +107,10 @@ ftrace_call:
 #endif
 
        /* Restore gprs */
-       REST_8GPRS(0,r1)
-       REST_8GPRS(8,r1)
-       REST_8GPRS(16,r1)
-       REST_8GPRS(24,r1)
+       REST_GPR(0,r1)
+       REST_10GPRS(2,r1)
+       REST_10GPRS(12,r1)
+       REST_10GPRS(22,r1)
 
        /* Restore possibly modified LR */
        ld      r0, _LINK(r1)