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s390: remove critical section cleanup from entry.S

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The current code is rather complex and caused a lot of subtle
and hard to debug bugs in the past. Simplify the code by calling
the system_call handler with interrupts disabled, save
machine state, and re-enable them later.

This requires significant changes to the machine check handling code
as well. When the machine check interrupt arrived while being in kernel
mode the new code will signal pending machine checks with a SIGP external
call. When userspace was interrupted, the handler will switch to the
kernel stack and directly execute s390_handle_mcck().

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Sven Schnelle
2020-02-20 12:09:36 +01:00
committed by Vasily Gorbik
parent 11886c199d
commit 0b0ed657fe
9 changed files with 143 additions and 390 deletions
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18
arch/s390/include/asm/processor.h
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@@ -14,17 +14,15 @@
#include <linux/bits.h>
#define CIF_MCCK_PENDING 0 /* machine check handling is pending */
#define CIF_ASCE_PRIMARY 1 /* primary asce needs fixup / uaccess */
#define CIF_ASCE_SECONDARY 2 /* secondary asce needs fixup / uaccess */
#define CIF_NOHZ_DELAY 3 /* delay HZ disable for a tick */
#define CIF_FPU 4 /* restore FPU registers */
#define CIF_IGNORE_IRQ 5 /* ignore interrupt (for udelay) */
#define CIF_ENABLED_WAIT 6 /* in enabled wait state */
#define CIF_MCCK_GUEST 7 /* machine check happening in guest */
#define CIF_DEDICATED_CPU 8 /* this CPU is dedicated */
#define CIF_ASCE_PRIMARY 0 /* primary asce needs fixup / uaccess */
#define CIF_ASCE_SECONDARY 1 /* secondary asce needs fixup / uaccess */
#define CIF_NOHZ_DELAY 2 /* delay HZ disable for a tick */
#define CIF_FPU 3 /* restore FPU registers */
#define CIF_IGNORE_IRQ 4 /* ignore interrupt (for udelay) */
#define CIF_ENABLED_WAIT 5 /* in enabled wait state */
#define CIF_MCCK_GUEST 6 /* machine check happening in guest */
#define CIF_DEDICATED_CPU 7 /* this CPU is dedicated */
#define _CIF_MCCK_PENDING BIT(CIF_MCCK_PENDING)
#define _CIF_ASCE_PRIMARY BIT(CIF_ASCE_PRIMARY)
#define _CIF_ASCE_SECONDARY BIT(CIF_ASCE_SECONDARY)
#define _CIF_NOHZ_DELAY BIT(CIF_NOHZ_DELAY)