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Diffstat (limited to 'arch/powerpc/lib/sstep.c')
-rw-r--r--arch/powerpc/lib/sstep.c218
1 files changed, 160 insertions, 58 deletions
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index ae5189ab004..5c09f365c84 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -11,6 +11,7 @@
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/ptrace.h>
+#include <linux/prefetch.h>
#include <asm/sstep.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
@@ -45,6 +46,18 @@ extern int do_stxvd2x(int rn, unsigned long ea);
#endif
/*
+ * Emulate the truncation of 64 bit values in 32-bit mode.
+ */
+static unsigned long truncate_if_32bit(unsigned long msr, unsigned long val)
+{
+#ifdef __powerpc64__
+ if ((msr & MSR_64BIT) == 0)
+ val &= 0xffffffffUL;
+#endif
+ return val;
+}
+
+/*
* Determine whether a conditional branch instruction would branch.
*/
static int __kprobes branch_taken(unsigned int instr, struct pt_regs *regs)
@@ -87,14 +100,13 @@ static unsigned long __kprobes dform_ea(unsigned int instr, struct pt_regs *regs
ea = (signed short) instr; /* sign-extend */
if (ra) {
ea += regs->gpr[ra];
- if (instr & 0x04000000) /* update forms */
- regs->gpr[ra] = ea;
+ if (instr & 0x04000000) { /* update forms */
+ if ((instr>>26) != 47) /* stmw is not an update form */
+ regs->gpr[ra] = ea;
+ }
}
-#ifdef __powerpc64__
- if (!(regs->msr & MSR_SF))
- ea &= 0xffffffffUL;
-#endif
- return ea;
+
+ return truncate_if_32bit(regs->msr, ea);
}
#ifdef __powerpc64__
@@ -113,9 +125,8 @@ static unsigned long __kprobes dsform_ea(unsigned int instr, struct pt_regs *reg
if ((instr & 3) == 1) /* update forms */
regs->gpr[ra] = ea;
}
- if (!(regs->msr & MSR_SF))
- ea &= 0xffffffffUL;
- return ea;
+
+ return truncate_if_32bit(regs->msr, ea);
}
#endif /* __powerpc64 */
@@ -136,11 +147,8 @@ static unsigned long __kprobes xform_ea(unsigned int instr, struct pt_regs *regs
if (do_update) /* update forms */
regs->gpr[ra] = ea;
}
-#ifdef __powerpc64__
- if (!(regs->msr & MSR_SF))
- ea &= 0xffffffffUL;
-#endif
- return ea;
+
+ return truncate_if_32bit(regs->msr, ea);
}
/*
@@ -204,11 +212,19 @@ static int __kprobes read_mem_unaligned(unsigned long *dest, unsigned long ea,
{
int err;
unsigned long x, b, c;
+#ifdef __LITTLE_ENDIAN__
+ int len = nb; /* save a copy of the length for byte reversal */
+#endif
/* unaligned, do this in pieces */
x = 0;
for (; nb > 0; nb -= c) {
+#ifdef __LITTLE_ENDIAN__
+ c = 1;
+#endif
+#ifdef __BIG_ENDIAN__
c = max_align(ea);
+#endif
if (c > nb)
c = max_align(nb);
err = read_mem_aligned(&b, ea, c);
@@ -217,7 +233,24 @@ static int __kprobes read_mem_unaligned(unsigned long *dest, unsigned long ea,
x = (x << (8 * c)) + b;
ea += c;
}
+#ifdef __LITTLE_ENDIAN__
+ switch (len) {
+ case 2:
+ *dest = byterev_2(x);
+ break;
+ case 4:
+ *dest = byterev_4(x);
+ break;
+#ifdef __powerpc64__
+ case 8:
+ *dest = byterev_8(x);
+ break;
+#endif
+ }
+#endif
+#ifdef __BIG_ENDIAN__
*dest = x;
+#endif
return 0;
}
@@ -265,15 +298,35 @@ static int __kprobes write_mem_unaligned(unsigned long val, unsigned long ea,
int err;
unsigned long c;
+#ifdef __LITTLE_ENDIAN__
+ switch (nb) {
+ case 2:
+ val = byterev_2(val);
+ break;
+ case 4:
+ val = byterev_4(val);
+ break;
+#ifdef __powerpc64__
+ case 8:
+ val = byterev_8(val);
+ break;
+#endif
+ }
+#endif
/* unaligned or little-endian, do this in pieces */
for (; nb > 0; nb -= c) {
+#ifdef __LITTLE_ENDIAN__
+ c = 1;
+#endif
+#ifdef __BIG_ENDIAN__
c = max_align(ea);
+#endif
if (c > nb)
c = max_align(nb);
err = write_mem_aligned(val >> (nb - c) * 8, ea, c);
if (err)
return err;
- ++ea;
+ ea += c;
}
return 0;
}
@@ -302,22 +355,36 @@ static int __kprobes do_fp_load(int rn, int (*func)(int, unsigned long),
struct pt_regs *regs)
{
int err;
- unsigned long val[sizeof(double) / sizeof(long)];
+ union {
+ double dbl;
+ unsigned long ul[2];
+ struct {
+#ifdef __BIG_ENDIAN__
+ unsigned _pad_;
+ unsigned word;
+#endif
+#ifdef __LITTLE_ENDIAN__
+ unsigned word;
+ unsigned _pad_;
+#endif
+ } single;
+ } data;
unsigned long ptr;
if (!address_ok(regs, ea, nb))
return -EFAULT;
if ((ea & 3) == 0)
return (*func)(rn, ea);
- ptr = (unsigned long) &val[0];
+ ptr = (unsigned long) &data.ul;
if (sizeof(unsigned long) == 8 || nb == 4) {
- err = read_mem_unaligned(&val[0], ea, nb, regs);
- ptr += sizeof(unsigned long) - nb;
+ err = read_mem_unaligned(&data.ul[0], ea, nb, regs);
+ if (nb == 4)
+ ptr = (unsigned long)&(data.single.word);
} else {
/* reading a double on 32-bit */
- err = read_mem_unaligned(&val[0], ea, 4, regs);
+ err = read_mem_unaligned(&data.ul[0], ea, 4, regs);
if (!err)
- err = read_mem_unaligned(&val[1], ea + 4, 4, regs);
+ err = read_mem_unaligned(&data.ul[1], ea + 4, 4, regs);
}
if (err)
return err;
@@ -329,28 +396,42 @@ static int __kprobes do_fp_store(int rn, int (*func)(int, unsigned long),
struct pt_regs *regs)
{
int err;
- unsigned long val[sizeof(double) / sizeof(long)];
+ union {
+ double dbl;
+ unsigned long ul[2];
+ struct {
+#ifdef __BIG_ENDIAN__
+ unsigned _pad_;
+ unsigned word;
+#endif
+#ifdef __LITTLE_ENDIAN__
+ unsigned word;
+ unsigned _pad_;
+#endif
+ } single;
+ } data;
unsigned long ptr;
if (!address_ok(regs, ea, nb))
return -EFAULT;
if ((ea & 3) == 0)
return (*func)(rn, ea);
- ptr = (unsigned long) &val[0];
+ ptr = (unsigned long) &data.ul[0];
if (sizeof(unsigned long) == 8 || nb == 4) {
- ptr += sizeof(unsigned long) - nb;
+ if (nb == 4)
+ ptr = (unsigned long)&(data.single.word);
err = (*func)(rn, ptr);
if (err)
return err;
- err = write_mem_unaligned(val[0], ea, nb, regs);
+ err = write_mem_unaligned(data.ul[0], ea, nb, regs);
} else {
/* writing a double on 32-bit */
err = (*func)(rn, ptr);
if (err)
return err;
- err = write_mem_unaligned(val[0], ea, 4, regs);
+ err = write_mem_unaligned(data.ul[0], ea, 4, regs);
if (!err)
- err = write_mem_unaligned(val[1], ea + 4, 4, regs);
+ err = write_mem_unaligned(data.ul[1], ea + 4, 4, regs);
}
return err;
}
@@ -466,7 +547,7 @@ static void __kprobes set_cr0(struct pt_regs *regs, int rd)
regs->ccr = (regs->ccr & 0x0fffffff) | ((regs->xer >> 3) & 0x10000000);
#ifdef __powerpc64__
- if (!(regs->msr & MSR_SF))
+ if (!(regs->msr & MSR_64BIT))
val = (int) val;
#endif
if (val < 0)
@@ -487,7 +568,7 @@ static void __kprobes add_with_carry(struct pt_regs *regs, int rd,
++val;
regs->gpr[rd] = val;
#ifdef __powerpc64__
- if (!(regs->msr & MSR_SF)) {
+ if (!(regs->msr & MSR_64BIT)) {
val = (unsigned int) val;
val1 = (unsigned int) val1;
}
@@ -560,7 +641,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
unsigned long int ea;
unsigned int cr, mb, me, sh;
int err;
- unsigned long old_ra;
+ unsigned long old_ra, val3;
long ival;
opcode = instr >> 26;
@@ -570,12 +651,11 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
if ((instr & 2) == 0)
imm += regs->nip;
regs->nip += 4;
- if ((regs->msr & MSR_SF) == 0)
- regs->nip &= 0xffffffffUL;
+ regs->nip = truncate_if_32bit(regs->msr, regs->nip);
if (instr & 1)
regs->link = regs->nip;
if (branch_taken(instr, regs))
- regs->nip = imm;
+ regs->nip = truncate_if_32bit(regs->msr, imm);
return 1;
#ifdef CONFIG_PPC64
case 17: /* sc */
@@ -604,13 +684,9 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
imm -= 0x04000000;
if ((instr & 2) == 0)
imm += regs->nip;
- if (instr & 1) {
- regs->link = regs->nip + 4;
- if ((regs->msr & MSR_SF) == 0)
- regs->link &= 0xffffffffUL;
- }
- if ((regs->msr & MSR_SF) == 0)
- imm &= 0xffffffffUL;
+ if (instr & 1)
+ regs->link = truncate_if_32bit(regs->msr, regs->nip + 4);
+ imm = truncate_if_32bit(regs->msr, imm);
regs->nip = imm;
return 1;
case 19:
@@ -618,11 +694,8 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
case 16: /* bclr */
case 528: /* bcctr */
imm = (instr & 0x400)? regs->ctr: regs->link;
- regs->nip += 4;
- if ((regs->msr & MSR_SF) == 0) {
- regs->nip &= 0xffffffffUL;
- imm &= 0xffffffffUL;
- }
+ regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
+ imm = truncate_if_32bit(regs->msr, imm);
if (instr & 1)
regs->link = regs->nip;
if (branch_taken(instr, regs))
@@ -1125,7 +1198,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
sh = regs->gpr[rb] & 0x3f;
ival = (signed int) regs->gpr[rd];
regs->gpr[ra] = ival >> (sh < 32 ? sh : 31);
- if (ival < 0 && (sh >= 32 || (ival & ((1 << sh) - 1)) != 0))
+ if (ival < 0 && (sh >= 32 || (ival & ((1ul << sh) - 1)) != 0))
regs->xer |= XER_CA;
else
regs->xer &= ~XER_CA;
@@ -1135,7 +1208,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
sh = rb;
ival = (signed int) regs->gpr[rd];
regs->gpr[ra] = ival >> sh;
- if (ival < 0 && (ival & ((1 << sh) - 1)) != 0)
+ if (ival < 0 && (ival & ((1ul << sh) - 1)) != 0)
regs->xer |= XER_CA;
else
regs->xer &= ~XER_CA;
@@ -1143,7 +1216,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
#ifdef __powerpc64__
case 27: /* sld */
- sh = regs->gpr[rd] & 0x7f;
+ sh = regs->gpr[rb] & 0x7f;
if (sh < 64)
regs->gpr[ra] = regs->gpr[rd] << sh;
else
@@ -1162,7 +1235,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
sh = regs->gpr[rb] & 0x7f;
ival = (signed long int) regs->gpr[rd];
regs->gpr[ra] = ival >> (sh < 64 ? sh : 63);
- if (ival < 0 && (sh >= 64 || (ival & ((1 << sh) - 1)) != 0))
+ if (ival < 0 && (sh >= 64 || (ival & ((1ul << sh) - 1)) != 0))
regs->xer |= XER_CA;
else
regs->xer &= ~XER_CA;
@@ -1173,7 +1246,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
sh = rb | ((instr & 2) << 4);
ival = (signed long int) regs->gpr[rd];
regs->gpr[ra] = ival >> sh;
- if (ival < 0 && (ival & ((1 << sh) - 1)) != 0)
+ if (ival < 0 && (ival & ((1ul << sh) - 1)) != 0)
regs->xer |= XER_CA;
else
regs->xer &= ~XER_CA;
@@ -1397,7 +1470,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
regs->gpr[rd] = byterev_4(val);
goto ldst_done;
-#ifdef CONFIG_PPC_CPU
+#ifdef CONFIG_PPC_FPU
case 535: /* lfsx */
case 567: /* lfsux */
if (!(regs->msr & MSR_FP))
@@ -1488,11 +1561,44 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
goto ldst_done;
case 36: /* stw */
- case 37: /* stwu */
val = regs->gpr[rd];
err = write_mem(val, dform_ea(instr, regs), 4, regs);
goto ldst_done;
+ case 37: /* stwu */
+ val = regs->gpr[rd];
+ val3 = dform_ea(instr, regs);
+ /*
+ * For PPC32 we always use stwu to change stack point with r1. So
+ * this emulated store may corrupt the exception frame, now we
+ * have to provide the exception frame trampoline, which is pushed
+ * below the kprobed function stack. So we only update gpr[1] but
+ * don't emulate the real store operation. We will do real store
+ * operation safely in exception return code by checking this flag.
+ */
+ if ((ra == 1) && !(regs->msr & MSR_PR) \
+ && (val3 >= (regs->gpr[1] - STACK_INT_FRAME_SIZE))) {
+#ifdef CONFIG_PPC32
+ /*
+ * Check if we will touch kernel sack overflow
+ */
+ if (val3 - STACK_INT_FRAME_SIZE <= current->thread.ksp_limit) {
+ printk(KERN_CRIT "Can't kprobe this since Kernel stack overflow.\n");
+ err = -EINVAL;
+ break;
+ }
+#endif /* CONFIG_PPC32 */
+ /*
+ * Check if we already set since that means we'll
+ * lose the previous value.
+ */
+ WARN_ON(test_thread_flag(TIF_EMULATE_STACK_STORE));
+ set_thread_flag(TIF_EMULATE_STACK_STORE);
+ err = 0;
+ } else
+ err = write_mem(val, val3, 4, regs);
+ goto ldst_done;
+
case 38: /* stb */
case 39: /* stbu */
val = regs->gpr[rd];
@@ -1616,11 +1722,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
return 0; /* invoke DSI if -EFAULT? */
}
instr_done:
- regs->nip += 4;
-#ifdef __powerpc64__
- if ((regs->msr & MSR_SF) == 0)
- regs->nip &= 0xffffffffUL;
-#endif
+ regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
return 1;
logical_done:
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-05 00:26:04 +0000