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Commit a71d1d6b authored by David S. Miller's avatar David S. Miller
Browse files

sparc64: Give a stack frame to the ftrace call sites. 



It's the only way we'll be able to implement the function
graph tracer properly.

A positive is that we no longer have to worry about the
linker over-optimizing the tail call, since we don't
use a tail call any more.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent daecbf58

arch/sparc/lib/mcount.S

+16 −15
Original line number Diff line number Diff line
@@ -33,9 +33,13 @@ mcount: 
	or		%g2, %lo(ftrace_stub), %g2

	cmp		%g1, %g2

	be,pn		%icc, 1f

	 mov		%i7, %o1

	jmpl		%g1, %g0

	 mov		%o7, %o0

	 mov		%i7, %g2

	save		%sp, -128, %sp

	mov		%g2, %o1

	jmpl		%g1, %o7

	 mov		%i7, %o0

	ret

	 restore

	/* not reached */

1:

#endif
@@ -57,21 +61,18 @@ ftrace_stub: 
	.type		ftrace_caller,#function

ftrace_caller:

	sethi		%hi(function_trace_stop), %g1

	mov		%i7, %o1

	lduw		[%g1 + %lo(function_trace_stop)], %g2

	brnz,pn		%g2, ftrace_stub

	 mov		%o7, %o0

	mov		%i7, %g2

	lduw		[%g1 + %lo(function_trace_stop)], %g3

	brnz,pn		%g3, ftrace_stub

	 nop

	save		%sp, -128, %sp

	mov		%g2, %o1

	.globl		ftrace_call

ftrace_call:

	/* If the final kernel link ever turns on relaxation, we'll need

	 * to do something about this tail call.  Otherwise the linker

	 * will rewrite the call into a branch and nop out the move

	 * instruction.

	 */

	call		ftrace_stub

	 mov		%o0, %o7

	retl

	 nop

	 mov		%i7, %o0

	ret

	 restore

	.size		ftrace_call,.-ftrace_call

	.size		ftrace_caller,.-ftrace_caller

#endif