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powerpc/64s: Move system_call() symbol to just after setting MSR_EE 

It is common to get a PMU interrupt right after the mtmsr instruction that
enables interrupts. Due to this, the stack trace profile gets needlessly split
across system_call_common() and system_call().

Previously, system_call() symbol was at the current place to hide a few
earlier symbols which have since been made private or removed entirely.

So, let's move system_call() slightly higher up, right after the mtmsr
instruction that enables interrupts. Convert existing references to
system_call to a local syscall symbol.

Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Naveen N. Rao 2017-06-29 23:19:17 +05:30 committed by Michael Ellerman
parent cf7d6fb067
commit 266de3a842
1 changed files with 4 additions and 3 deletions
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7
arch/powerpc/kernel/entry_64.S
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@ -143,6 +143,7 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
mtmsrd r11,1
#endif /* CONFIG_PPC_BOOK3E */
system_call: /* label this so stack traces look sane */
/* We do need to set SOFTE in the stack frame or the return
* from interrupt will be painful
*/
@ -156,7 +157,7 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
cmpldi 0,r0,NR_syscalls
bge- .Lsyscall_enosys
system_call: /* label this so stack traces look sane */
.Lsyscall:
/*
* Need to vector to 32 Bit or default sys_call_table here,
* based on caller's run-mode / personality.
@ -310,13 +311,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
ld r7,GPR7(r1)
ld r8,GPR8(r1)
/* Repopulate r9 and r10 for the system_call path */
/* Repopulate r9 and r10 for the syscall path */
addi r9,r1,STACK_FRAME_OVERHEAD
CURRENT_THREAD_INFO(r10, r1)
ld r10,TI_FLAGS(r10)
cmpldi r0,NR_syscalls
blt+ system_call
blt+ .Lsyscall
/* Return code is already in r3 thanks to do_syscall_trace_enter() */
b .Lsyscall_exit