Commit a4979a7e authored Jun 01, 2017 by Naveen N. Rao Committed by Michael Ellerman Jun 16, 2017

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: 15308664 ("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>

parent a9f8553e

arch/powerpc/kernel/trace/ftrace_64_mprofile.S

+12 −8

Original line number	Diff line number	Diff line
		@@ -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)