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-rw-r--r--arch/s390/include/asm/fpu/api.h34
-rw-r--r--arch/s390/kernel/compat_signal.c4
-rw-r--r--arch/s390/kernel/fpu.c4
-rw-r--r--arch/s390/kernel/ptrace.c13
-rw-r--r--arch/s390/kernel/signal.c4
-rw-r--r--arch/s390/kernel/vmlinux.lds.S1
-rw-r--r--arch/s390/kvm/kvm-s390.c5
7 files changed, 29 insertions, 36 deletions
diff --git a/arch/s390/include/asm/fpu/api.h b/arch/s390/include/asm/fpu/api.h
index b714ed0ef688..dc34de234ed7 100644
--- a/arch/s390/include/asm/fpu/api.h
+++ b/arch/s390/include/asm/fpu/api.h
@@ -51,21 +51,27 @@ void save_fpu_regs(void);
void load_fpu_regs(void);
void __load_fpu_regs(void);
-static inline int test_fp_ctl(u32 fpc)
+/**
+ * sfpc_safe - Set floating point control register safely.
+ * @fpc: new value for floating point control register
+ *
+ * Set floating point control register. This may lead to an exception,
+ * since a saved value may have been modified by user space (ptrace,
+ * signal return, kvm registers) to an invalid value. In such a case
+ * set the floating point control register to zero.
+ */
+static inline void sfpc_safe(u32 fpc)
{
- u32 orig_fpc;
- int rc;
-
- asm volatile(
- " efpc %1\n"
- " sfpc %2\n"
- "0: sfpc %1\n"
- " la %0,0\n"
- "1:\n"
- EX_TABLE(0b,1b)
- : "=d" (rc), "=&d" (orig_fpc)
- : "d" (fpc), "0" (-EINVAL));
- return rc;
+ asm volatile("\n"
+ "0: sfpc %[fpc]\n"
+ "1: nopr %%r7\n"
+ ".pushsection .fixup, \"ax\"\n"
+ "2: lghi %[fpc],0\n"
+ " jg 0b\n"
+ ".popsection\n"
+ EX_TABLE(1b, 2b)
+ : [fpc] "+d" (fpc)
+ : : "memory");
}
#define KERNEL_FPC 1
diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c
index cecedd01d4ec..8b90bf89b62c 100644
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -98,10 +98,6 @@ static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW32_MASK_RI))
return -EINVAL;
- /* Test the floating-point-control word. */
- if (test_fp_ctl(user_sregs.fpregs.fpc))
- return -EINVAL;
-
/* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
(__u64)(user_sregs.regs.psw.mask & PSW32_MASK_USER) << 32 |
diff --git a/arch/s390/kernel/fpu.c b/arch/s390/kernel/fpu.c
index 4666b29ac8a1..35aaf99bab16 100644
--- a/arch/s390/kernel/fpu.c
+++ b/arch/s390/kernel/fpu.c
@@ -177,10 +177,10 @@ EXPORT_SYMBOL(__kernel_fpu_end);
void __load_fpu_regs(void)
{
- struct fpu *state = &current->thread.fpu;
unsigned long *regs = current->thread.fpu.regs;
+ struct fpu *state = &current->thread.fpu;
- asm volatile("lfpc %0" : : "Q" (state->fpc));
+ sfpc_safe(state->fpc);
if (likely(MACHINE_HAS_VX)) {
asm volatile("lgr 1,%0\n"
"VLM 0,15,0,1\n"
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index c7ed302a6b59..df2ee1b88024 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -392,9 +392,7 @@ static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
/*
* floating point control reg. is in the thread structure
*/
- save_fpu_regs();
- if ((unsigned int) data != 0 ||
- test_fp_ctl(data >> (BITS_PER_LONG - 32)))
+ if ((unsigned int)data != 0)
return -EINVAL;
child->thread.fpu.fpc = data >> (BITS_PER_LONG - 32);
@@ -749,9 +747,6 @@ static int __poke_user_compat(struct task_struct *child,
/*
* floating point control reg. is in the thread structure
*/
- save_fpu_regs();
- if (test_fp_ctl(tmp))
- return -EINVAL;
child->thread.fpu.fpc = data;
} else if (addr < offsetof(struct compat_user, regs.fp_regs) + sizeof(s390_fp_regs)) {
@@ -913,7 +908,9 @@ static int s390_fpregs_set(struct task_struct *target,
int rc = 0;
freg_t fprs[__NUM_FPRS];
- save_fpu_regs();
+ if (target == current)
+ save_fpu_regs();
+
if (MACHINE_HAS_VX)
convert_vx_to_fp(fprs, target->thread.fpu.vxrs);
else
@@ -926,7 +923,7 @@ static int s390_fpregs_set(struct task_struct *target,
0, offsetof(s390_fp_regs, fprs));
if (rc)
return rc;
- if (ufpc[1] != 0 || test_fp_ctl(ufpc[0]))
+ if (ufpc[1] != 0)
return -EINVAL;
target->thread.fpu.fpc = ufpc[0];
}
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index d63557d3868c..0e926e896808 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -149,10 +149,6 @@ static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
return -EINVAL;
- /* Test the floating-point-control word. */
- if (test_fp_ctl(user_sregs.fpregs.fpc))
- return -EINVAL;
-
/* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
regs->psw.mask = (regs->psw.mask & ~(PSW_MASK_USER | PSW_MASK_RI)) |
(user_sregs.regs.psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S
index 2ae201ebf90b..e32ef446f451 100644
--- a/arch/s390/kernel/vmlinux.lds.S
+++ b/arch/s390/kernel/vmlinux.lds.S
@@ -52,6 +52,7 @@ SECTIONS
SOFTIRQENTRY_TEXT
FTRACE_HOTPATCH_TRAMPOLINES_TEXT
*(.text.*_indirect_*)
+ *(.fixup)
*(.gnu.warning)
. = ALIGN(PAGE_SIZE);
_etext = .; /* End of text section */
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 1a1af4db5afc..432688acc523 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -4962,10 +4962,7 @@ static void sync_regs(struct kvm_vcpu *vcpu)
current->thread.fpu.regs = vcpu->run->s.regs.vrs;
else
current->thread.fpu.regs = vcpu->run->s.regs.fprs;
- current->thread.fpu.fpc = READ_ONCE(vcpu->run->s.regs.fpc);
- if (test_fp_ctl(current->thread.fpu.fpc))
- /* User space provided an invalid FPC, let's clear it */
- current->thread.fpu.fpc = 0;
+ current->thread.fpu.fpc = vcpu->run->s.regs.fpc;
/* Sync fmt2 only data */
if (likely(!kvm_s390_pv_cpu_is_protected(vcpu))) {
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-17 06:37:06 +0000