Commit f96cb0d6 authored by Claudio Imbrenda's avatar Claudio Imbrenda Committed by Heiko Carstens
Browse files

s390/entry: Remove __GMAP_ASCE and use _PIF_GUEST_FAULT again 



Now that the guest ASCE is passed as a parameter to __sie64a(),
_PIF_GUEST_FAULT can be used again to determine whether the fault was a
guest or host fault.

Since the guest ASCE will not be taken from the gmap pointer in lowcore
anymore, __GMAP_ASCE can be removed. For the same reason the guest
ASCE needs now to be saved into the cr1 save area unconditionally.

Signed-off-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: default avatarJanosch Frank <frankja@linux.ibm.com>
Reviewed-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20241022120601.167009-2-imbrenda@linux.ibm.com


Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
parent f4d5e64c

arch/s390/include/asm/ptrace.h

+2 −0
Original line number Diff line number Diff line
@@ -14,11 +14,13 @@ 
#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)

arch/s390/kernel/asm-offsets.c

+0 −2
Original line number Diff line number Diff line
@@ -13,7 +13,6 @@ 
#include <linux/purgatory.h>

#include <linux/pgtable.h>

#include <linux/ftrace.h>

#include <asm/gmap.h>

#include <asm/stacktrace.h>



int main(void)
@@ -161,7 +160,6 @@ int main(void) 
	OFFSET(__LC_PGM_TDB, lowcore, pgm_tdb);

	BLANK();

	/* gmap/sie offsets */

	OFFSET(__GMAP_ASCE, gmap, asce);

	OFFSET(__SIE_PROG0C, kvm_s390_sie_block, prog0c);

	OFFSET(__SIE_PROG20, kvm_s390_sie_block, prog20);

	/* kexec_sha_region */

arch/s390/kernel/entry.S

+14 −12
Original line number Diff line number Diff line
@@ -327,13 +327,23 @@ SYM_CODE_START(pgm_check_handler) 
	GET_LC	%r13

	stpt	__LC_SYS_ENTER_TIMER(%r13)

	BPOFF

	lgr	%r10,%r15

	lmg	%r8,%r9,__LC_PGM_OLD_PSW(%r13)

	xgr	%r10,%r10

	xgr	%r12,%r12

	tmhh	%r8,0x0001		# coming from user space?

	jno	.Lpgm_skip_asce

	lctlg	%c1,%c1,__LC_KERNEL_ASCE(%r13)

	j	3f			# -> fault in user space

.Lpgm_skip_asce:

#if IS_ENABLED(CONFIG_KVM)

	lg	%r11,__LC_CURRENT(%r13)

	tm	__TI_sie(%r11),0xff

	jz	1f

	BPENTER	__SF_SIE_FLAGS(%r15),_TIF_ISOLATE_BP_GUEST

	SIEEXIT __SF_SIE_CONTROL(%r15),%r13

	lg	%r12,__SF_SIE_GUEST_ASCE(%r15)

	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(%r13),0x80	# check for per exception
@@ -344,21 +354,13 @@ SYM_CODE_START(pgm_check_handler) 
	CHECK_VMAP_STACK __LC_SAVE_AREA,%r13,4f

3:	lg	%r15,__LC_KERNEL_STACK(%r13)

4:	la	%r11,STACK_FRAME_OVERHEAD(%r15)

	xc	__PT_FLAGS(8,%r11),__PT_FLAGS(%r11)

	stg	%r10,__PT_FLAGS(%r11)

	stg	%r12,__PT_CR1(%r11)

	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)

	stmg	%r0,%r7,__PT_R0(%r11)

	mvc	__PT_R8(64,%r11),__LC_SAVE_AREA(%r13)

	mvc	__PT_LAST_BREAK(8,%r11),__LC_PGM_LAST_BREAK(%r13)

	stctg	%c1,%c1,__PT_CR1(%r11)

#if IS_ENABLED(CONFIG_KVM)

	ltg	%r12,__LC_GMAP(%r13)

	jz	5f

	clc	__GMAP_ASCE(8,%r12), __PT_CR1(%r11)

	jne	5f

	BPENTER	__SF_SIE_FLAGS(%r10),_TIF_ISOLATE_BP_GUEST

	SIEEXIT __SF_SIE_CONTROL(%r10),%r13

#endif

5:	stmg	%r8,%r9,__PT_PSW(%r11)

	stmg	%r8,%r9,__PT_PSW(%r11)

	# clear user controlled registers to prevent speculative use

	xgr	%r0,%r0

	xgr	%r1,%r1

arch/s390/mm/fault.c

+2 −4
Original line number Diff line number Diff line
@@ -68,15 +68,13 @@ 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;

		gmap = (struct gmap *)get_lowcore()->gmap;

		if (gmap && gmap->asce == regs->cr1)

		if (test_pt_regs_flag(regs, PIF_GUEST_FAULT))

			return GMAP_FAULT;

		return KERNEL_FAULT;

	}
@@ -187,7 +185,7 @@ static void dump_fault_info(struct pt_regs *regs) 
		pr_cont("user ");

		break;

	case GMAP_FAULT:

		asce = ((struct gmap *)get_lowcore()->gmap)->asce;

		asce = regs->cr1;

		pr_cont("gmap ");

		break;

	case KERNEL_FAULT: