Commit 620f5c59 authored by Rohan McLure's avatar Rohan McLure Committed by Michael Ellerman
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powerpc/64s: Fix comment on interrupt handler prologue 



Interrupt handlers on 64s systems will often need to save register state
from the interrupted process to make space for loading special purpose
registers or for internal state.

Fix a comment documenting a common code path macro in the beginning of
interrupt handlers where r10 is saved to the PACA to afford space for
the value of the CFAR. Comment is currently written as if r10-r12 are
saved to PACA, but in fact only r10 is saved, with r11-r12 saved much
later. The distance in code between these saves has grown over the many
revisions of this macro. Fix this by signalling with a comment where
r11-r12 are saved to the PACA.

Signed-off-by: default avatarRohan McLure <rmclure@linux.ibm.com>
Reported-by: default avatarNicholas Piggin <npiggin@gmail.com>
Reviewed-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220921065605.1051927-8-rmclure@linux.ibm.com
parent 53ecaa67

arch/powerpc/kernel/exceptions-64s.S

+2 −2
Original line number Diff line number Diff line
@@ -281,7 +281,7 @@ BEGIN_FTR_SECTION 
	mfspr	r9,SPRN_PPR

END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)

	HMT_MEDIUM

	std	r10,IAREA+EX_R10(r13)		/* save r10 - r12 */

	std	r10,IAREA+EX_R10(r13)		/* save r10 */

	.if ICFAR

BEGIN_FTR_SECTION

	mfspr	r10,SPRN_CFAR
@@ -321,7 +321,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR) 
	mfctr	r10

	std	r10,IAREA+EX_CTR(r13)

	mfcr	r9

	std	r11,IAREA+EX_R11(r13)

	std	r11,IAREA+EX_R11(r13)		/* save r11 - r12 */

	std	r12,IAREA+EX_R12(r13)



	/*