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authorSven Schnelle <svens@linux.ibm.com>2024-03-13 09:51:22 +0100
committerHeiko Carstens <hca@linux.ibm.com>2024-03-17 19:08:50 +0100
commit64c3431808bdab2ccef97d7a444018c416b080b5 (patch)
tree86657c918eb6219cb77e73670da92783a9ec694a /arch
parent29e5bc0f023a1110d1539d75ccac3b4cdcadec5e (diff)
s390/entry: compare gmap asce to determine guest/host fault
With the current implementation, there are some cornercases where a host fault would be treated as a guest fault, for example when the sie instruction causes a program check. Therefore store the gmap asce in ptregs, and use that to compare the primary asce from the fault instead of matching instruction addresses. Suggested-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/s390/include/asm/ptrace.h2
-rw-r--r--arch/s390/kernel/entry.S31
-rw-r--r--arch/s390/mm/fault.c4
3 files changed, 18 insertions, 19 deletions
diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h
index 788bc4467445..2ad9324f6338 100644
--- a/arch/s390/include/asm/ptrace.h
+++ b/arch/s390/include/asm/ptrace.h
@@ -14,13 +14,11 @@
#define PIF_SYSCALL 0 /* inside a system call */
#define PIF_EXECVE_PGSTE_RESTART 1 /* restart execve for PGSTE binaries */
#define PIF_SYSCALL_RET_SET 2 /* return value was set via ptrace */
-#define PIF_GUEST_FAULT 3 /* indicates program check in sie64a */
#define PIF_FTRACE_FULL_REGS 4 /* all register contents valid (ftrace) */
#define _PIF_SYSCALL BIT(PIF_SYSCALL)
#define _PIF_EXECVE_PGSTE_RESTART BIT(PIF_EXECVE_PGSTE_RESTART)
#define _PIF_SYSCALL_RET_SET BIT(PIF_SYSCALL_RET_SET)
-#define _PIF_GUEST_FAULT BIT(PIF_GUEST_FAULT)
#define _PIF_FTRACE_FULL_REGS BIT(PIF_FTRACE_FULL_REGS)
#define PSW32_MASK_PER _AC(0x40000000, UL)
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index a0543db0bcae..787394978bc0 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -119,8 +119,8 @@ _LPP_OFFSET = __LC_LPP
.endm
#if IS_ENABLED(CONFIG_KVM)
- .macro SIEEXIT
- lg %r9,__SF_SIE_CONTROL(%r15) # get control block pointer
+ .macro SIEEXIT sie_control
+ lg %r9,\sie_control # get control block pointer
ni __SIE_PROG0C+3(%r9),0xfe # no longer in SIE
lctlg %c1,%c1,__LC_KERNEL_ASCE # load primary asce
ni __LC_CPU_FLAGS+7,255-_CIF_SIE
@@ -316,21 +316,13 @@ SYM_CODE_START(pgm_check_handler)
stpt __LC_SYS_ENTER_TIMER
BPOFF
stmg %r8,%r15,__LC_SAVE_AREA_SYNC
- lghi %r10,0
+ lgr %r10,%r15
lmg %r8,%r9,__LC_PGM_OLD_PSW
tmhh %r8,0x0001 # coming from user space?
jno .Lpgm_skip_asce
lctlg %c1,%c1,__LC_KERNEL_ASCE
j 3f # -> fault in user space
.Lpgm_skip_asce:
-#if IS_ENABLED(CONFIG_KVM)
- # cleanup critical section for program checks in __sie64a
- TSTMSK __LC_CPU_FLAGS,_CIF_SIE
- jz 1f
- BPENTER __SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
- SIEEXIT
- lghi %r10,_PIF_GUEST_FAULT
-#endif
1: tmhh %r8,0x4000 # PER bit set in old PSW ?
jnz 2f # -> enabled, can't be a double fault
tm __LC_PGM_ILC+3,0x80 # check for per exception
@@ -341,13 +333,20 @@ SYM_CODE_START(pgm_check_handler)
CHECK_VMAP_STACK __LC_SAVE_AREA_SYNC,4f
3: lg %r15,__LC_KERNEL_STACK
4: la %r11,STACK_FRAME_OVERHEAD(%r15)
- stg %r10,__PT_FLAGS(%r11)
+ xc __PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
xc __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
stmg %r0,%r7,__PT_R0(%r11)
mvc __PT_R8(64,%r11),__LC_SAVE_AREA_SYNC
mvc __PT_LAST_BREAK(8,%r11),__LC_PGM_LAST_BREAK
- stmg %r8,%r9,__PT_PSW(%r11)
-
+ stctg %c1,%c1,__PT_CR1(%r11)
+#if IS_ENABLED(CONFIG_KVM)
+ lg %r12,__LC_GMAP
+ clc __GMAP_ASCE(8,%r12), __PT_CR1(%r11)
+ jne 5f
+ BPENTER __SF_SIE_FLAGS(%r10),_TIF_ISOLATE_BP_GUEST
+ SIEEXIT __SF_SIE_CONTROL(%r10)
+#endif
+5: stmg %r8,%r9,__PT_PSW(%r11)
# clear user controlled registers to prevent speculative use
xgr %r0,%r0
xgr %r1,%r1
@@ -399,7 +398,7 @@ SYM_CODE_START(\name)
TSTMSK __LC_CPU_FLAGS,_CIF_SIE
jz 0f
BPENTER __SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
- SIEEXIT
+ SIEEXIT __SF_SIE_CONTROL(%r15)
#endif
0: CHECK_STACK __LC_SAVE_AREA_ASYNC
aghi %r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
@@ -507,7 +506,7 @@ SYM_CODE_START(mcck_int_handler)
clgrjhe %r9,%r14, 4f
oi __LC_CPU_FLAGS+7, _CIF_MCCK_GUEST
4: BPENTER __SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST
- SIEEXIT
+ SIEEXIT __SF_SIE_CONTROL(%r15)
#endif
.Lmcck_user:
lg %r15,__LC_MCCK_STACK
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index ac4c78546d97..c421dd44ffbe 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -67,13 +67,15 @@ early_initcall(fault_init);
static enum fault_type get_fault_type(struct pt_regs *regs)
{
union teid teid = { .val = regs->int_parm_long };
+ struct gmap *gmap;
if (likely(teid.as == PSW_BITS_AS_PRIMARY)) {
if (user_mode(regs))
return USER_FAULT;
if (!IS_ENABLED(CONFIG_PGSTE))
return KERNEL_FAULT;
- if (test_pt_regs_flag(regs, PIF_GUEST_FAULT))
+ gmap = (struct gmap *)S390_lowcore.gmap;
+ if (regs->cr1 == gmap->asce)
return GMAP_FAULT;
return KERNEL_FAULT;
}