Commit 213400c4 authored Jul 22, 2024 by Heiko Carstens Committed by Vasily Gorbik Jul 23, 2024

s390/nmi: Simplify ptregs setup



The low level machine check handler code fills the ptregs structure
partially with the register contents present at machine check handler
entry and partially with contents from the machine check save area.

In case of a machine check the contents of all general purpose
registers are saved by the CPU to the machine check save area.
Therefore simplify the code and fill the ptregs structure by only
using the machine check save area as source.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

parent beb8cee0

arch/s390/kernel/entry.S

+2 −3

Original line number	Diff line number	Diff line
		@@ -491,8 +491,8 @@ SYM_CODE_START(mcck_int_handler)
		stctg %c1,%c1,__PT_CR1(%r11)
		lctlg %c1,%c1,__LC_KERNEL_ASCE
		xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
		lghi %r14,__LC_GPREGS_SAVE_AREA+64
		stmg %r0,%r7,__PT_R0(%r11)
		lghi %r14,__LC_GPREGS_SAVE_AREA
		mvc __PT_R0(128,%r11),0(%r14)
		# clear user controlled registers to prevent speculative use
		xgr %r0,%r0
		xgr %r1,%r1
		@@ -502,7 +502,6 @@ SYM_CODE_START(mcck_int_handler)
		xgr %r6,%r6
		xgr %r7,%r7
		xgr %r10,%r10
		mvc __PT_R8(64,%r11),0(%r14)
		stmg %r8,%r9,__PT_PSW(%r11)
		xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
		xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)