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-rw-r--r--arch/x86/include/asm/asm.h37
-rw-r--r--arch/x86/include/asm/extable.h6
-rw-r--r--arch/x86/include/asm/extable_fixup_types.h24
-rw-r--r--arch/x86/include/asm/insn-eval.h2
-rw-r--r--arch/x86/lib/insn-eval.c66
-rw-r--r--arch/x86/mm/extable.c40
-rw-r--r--arch/x86/net/bpf_jit_comp.c2
7 files changed, 145 insertions, 32 deletions
diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index 3a168483bc8e..c878fed3056f 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -152,6 +152,33 @@
#else /* ! __ASSEMBLY__ */
+# define DEFINE_EXTABLE_TYPE_REG \
+ ".macro extable_type_reg type:req reg:req\n" \
+ ".set found, 0\n" \
+ ".set regnr, 0\n" \
+ ".irp rs,rax,rcx,rdx,rbx,rsp,rbp,rsi,rdi,r8,r9,r10,r11,r12,r13,r14,r15\n" \
+ ".ifc \\reg, %%\\rs\n" \
+ ".set found, found+1\n" \
+ ".long \\type + (regnr << 8)\n" \
+ ".endif\n" \
+ ".set regnr, regnr+1\n" \
+ ".endr\n" \
+ ".set regnr, 0\n" \
+ ".irp rs,eax,ecx,edx,ebx,esp,ebp,esi,edi,r8d,r9d,r10d,r11d,r12d,r13d,r14d,r15d\n" \
+ ".ifc \\reg, %%\\rs\n" \
+ ".set found, found+1\n" \
+ ".long \\type + (regnr << 8)\n" \
+ ".endif\n" \
+ ".set regnr, regnr+1\n" \
+ ".endr\n" \
+ ".if (found != 1)\n" \
+ ".error \"extable_type_reg: bad register argument\"\n" \
+ ".endif\n" \
+ ".endm\n"
+
+# define UNDEFINE_EXTABLE_TYPE_REG \
+ ".purgem extable_type_reg\n"
+
# define _ASM_EXTABLE_TYPE(from, to, type) \
" .pushsection \"__ex_table\",\"a\"\n" \
" .balign 4\n" \
@@ -160,6 +187,16 @@
" .long " __stringify(type) " \n" \
" .popsection\n"
+# define _ASM_EXTABLE_TYPE_REG(from, to, type, reg) \
+ " .pushsection \"__ex_table\",\"a\"\n" \
+ " .balign 4\n" \
+ " .long (" #from ") - .\n" \
+ " .long (" #to ") - .\n" \
+ DEFINE_EXTABLE_TYPE_REG \
+ "extable_type_reg reg=" __stringify(reg) ", type=" __stringify(type) " \n"\
+ UNDEFINE_EXTABLE_TYPE_REG \
+ " .popsection\n"
+
/* For C file, we already have NOKPROBE_SYMBOL macro */
/*
diff --git a/arch/x86/include/asm/extable.h b/arch/x86/include/asm/extable.h
index 93f400eb728f..155c991ba95e 100644
--- a/arch/x86/include/asm/extable.h
+++ b/arch/x86/include/asm/extable.h
@@ -21,7 +21,7 @@
*/
struct exception_table_entry {
- int insn, fixup, type;
+ int insn, fixup, data;
};
struct pt_regs;
@@ -31,8 +31,8 @@ struct pt_regs;
do { \
(a)->fixup = (b)->fixup + (delta); \
(b)->fixup = (tmp).fixup - (delta); \
- (a)->type = (b)->type; \
- (b)->type = (tmp).type; \
+ (a)->data = (b)->data; \
+ (b)->data = (tmp).data; \
} while (0)
extern int fixup_exception(struct pt_regs *regs, int trapnr,
diff --git a/arch/x86/include/asm/extable_fixup_types.h b/arch/x86/include/asm/extable_fixup_types.h
index 4d709a2768bb..944f8329022a 100644
--- a/arch/x86/include/asm/extable_fixup_types.h
+++ b/arch/x86/include/asm/extable_fixup_types.h
@@ -2,6 +2,29 @@
#ifndef _ASM_X86_EXTABLE_FIXUP_TYPES_H
#define _ASM_X86_EXTABLE_FIXUP_TYPES_H
+/*
+ * Our IMM is signed, as such it must live at the top end of the word. Also,
+ * since C99 hex constants are of ambigious type, force cast the mask to 'int'
+ * so that FIELD_GET() will DTRT and sign extend the value when it extracts it.
+ */
+#define EX_DATA_TYPE_MASK ((int)0x000000FF)
+#define EX_DATA_REG_MASK ((int)0x00000F00)
+#define EX_DATA_FLAG_MASK ((int)0x0000F000)
+#define EX_DATA_IMM_MASK ((int)0xFFFF0000)
+
+#define EX_DATA_REG_SHIFT 8
+#define EX_DATA_FLAG_SHIFT 12
+#define EX_DATA_IMM_SHIFT 16
+
+#define EX_DATA_FLAG(flag) ((flag) << EX_DATA_FLAG_SHIFT)
+#define EX_DATA_IMM(imm) ((imm) << EX_DATA_IMM_SHIFT)
+
+/* flags */
+#define EX_FLAG_CLEAR_AX EX_DATA_FLAG(1)
+#define EX_FLAG_CLEAR_DX EX_DATA_FLAG(2)
+#define EX_FLAG_CLEAR_AX_DX EX_DATA_FLAG(3)
+
+/* types */
#define EX_TYPE_NONE 0
#define EX_TYPE_DEFAULT 1
#define EX_TYPE_FAULT 2
@@ -20,5 +43,6 @@
#define EX_TYPE_FAULT_MCE_SAFE 13
#define EX_TYPE_POP_ZERO 14
+#define EX_TYPE_IMM_REG 15 /* reg := (long)imm */
#endif
diff --git a/arch/x86/include/asm/insn-eval.h b/arch/x86/include/asm/insn-eval.h
index 4ec3613551e3..3df123f437c9 100644
--- a/arch/x86/include/asm/insn-eval.h
+++ b/arch/x86/include/asm/insn-eval.h
@@ -15,6 +15,8 @@
#define INSN_CODE_SEG_OPND_SZ(params) (params & 0xf)
#define INSN_CODE_SEG_PARAMS(oper_sz, addr_sz) (oper_sz | (addr_sz << 4))
+int pt_regs_offset(struct pt_regs *regs, int regno);
+
bool insn_has_rep_prefix(struct insn *insn);
void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs);
int insn_get_modrm_rm_off(struct insn *insn, struct pt_regs *regs);
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index eb3ccffb9b9d..7760d228041b 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -412,32 +412,39 @@ static short get_segment_selector(struct pt_regs *regs, int seg_reg_idx)
#endif /* CONFIG_X86_64 */
}
-static int get_reg_offset(struct insn *insn, struct pt_regs *regs,
- enum reg_type type)
+static const int pt_regoff[] = {
+ offsetof(struct pt_regs, ax),
+ offsetof(struct pt_regs, cx),
+ offsetof(struct pt_regs, dx),
+ offsetof(struct pt_regs, bx),
+ offsetof(struct pt_regs, sp),
+ offsetof(struct pt_regs, bp),
+ offsetof(struct pt_regs, si),
+ offsetof(struct pt_regs, di),
+#ifdef CONFIG_X86_64
+ offsetof(struct pt_regs, r8),
+ offsetof(struct pt_regs, r9),
+ offsetof(struct pt_regs, r10),
+ offsetof(struct pt_regs, r11),
+ offsetof(struct pt_regs, r12),
+ offsetof(struct pt_regs, r13),
+ offsetof(struct pt_regs, r14),
+ offsetof(struct pt_regs, r15),
+#endif
+};
+
+int pt_regs_offset(struct pt_regs *regs, int regno)
{
+ if ((unsigned)regno < ARRAY_SIZE(pt_regoff))
+ return pt_regoff[regno];
+ return -EDOM;
+}
+
+static int get_regno(struct insn *insn, enum reg_type type)
+{
+ int nr_registers = ARRAY_SIZE(pt_regoff);
int regno = 0;
- static const int regoff[] = {
- offsetof(struct pt_regs, ax),
- offsetof(struct pt_regs, cx),
- offsetof(struct pt_regs, dx),
- offsetof(struct pt_regs, bx),
- offsetof(struct pt_regs, sp),
- offsetof(struct pt_regs, bp),
- offsetof(struct pt_regs, si),
- offsetof(struct pt_regs, di),
-#ifdef CONFIG_X86_64
- offsetof(struct pt_regs, r8),
- offsetof(struct pt_regs, r9),
- offsetof(struct pt_regs, r10),
- offsetof(struct pt_regs, r11),
- offsetof(struct pt_regs, r12),
- offsetof(struct pt_regs, r13),
- offsetof(struct pt_regs, r14),
- offsetof(struct pt_regs, r15),
-#endif
- };
- int nr_registers = ARRAY_SIZE(regoff);
/*
* Don't possibly decode a 32-bit instructions as
* reading a 64-bit-only register.
@@ -505,7 +512,18 @@ static int get_reg_offset(struct insn *insn, struct pt_regs *regs,
WARN_ONCE(1, "decoded an instruction with an invalid register");
return -EINVAL;
}
- return regoff[regno];
+ return regno;
+}
+
+static int get_reg_offset(struct insn *insn, struct pt_regs *regs,
+ enum reg_type type)
+{
+ int regno = get_regno(insn, type);
+
+ if (regno < 0)
+ return regno;
+
+ return pt_regs_offset(regs, regno);
}
/**
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index fb0c4752df1a..cef8901b3e6f 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -2,12 +2,25 @@
#include <linux/extable.h>
#include <linux/uaccess.h>
#include <linux/sched/debug.h>
+#include <linux/bitfield.h>
#include <xen/xen.h>
#include <asm/fpu/api.h>
#include <asm/sev.h>
#include <asm/traps.h>
#include <asm/kdebug.h>
+#include <asm/insn-eval.h>
+
+static inline unsigned long *pt_regs_nr(struct pt_regs *regs, int nr)
+{
+ int reg_offset = pt_regs_offset(regs, nr);
+ static unsigned long __dummy;
+
+ if (WARN_ON_ONCE(reg_offset < 0))
+ return &__dummy;
+
+ return (unsigned long *)((unsigned long)regs + reg_offset);
+}
static inline unsigned long
ex_fixup_addr(const struct exception_table_entry *x)
@@ -15,10 +28,15 @@ ex_fixup_addr(const struct exception_table_entry *x)
return (unsigned long)&x->fixup + x->fixup;
}
-static bool ex_handler_default(const struct exception_table_entry *fixup,
+static bool ex_handler_default(const struct exception_table_entry *e,
struct pt_regs *regs)
{
- regs->ip = ex_fixup_addr(fixup);
+ if (e->data & EX_FLAG_CLEAR_AX)
+ regs->ax = 0;
+ if (e->data & EX_FLAG_CLEAR_DX)
+ regs->dx = 0;
+
+ regs->ip = ex_fixup_addr(e);
return true;
}
@@ -111,17 +129,25 @@ static bool ex_handler_pop_zero(const struct exception_table_entry *fixup,
return ex_handler_default(fixup, regs);
}
+static bool ex_handler_imm_reg(const struct exception_table_entry *fixup,
+ struct pt_regs *regs, int reg, int imm)
+{
+ *pt_regs_nr(regs, reg) = (long)imm;
+ return ex_handler_default(fixup, regs);
+}
+
int ex_get_fixup_type(unsigned long ip)
{
const struct exception_table_entry *e = search_exception_tables(ip);
- return e ? e->type : EX_TYPE_NONE;
+ return e ? FIELD_GET(EX_DATA_TYPE_MASK, e->data) : EX_TYPE_NONE;
}
int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code,
unsigned long fault_addr)
{
const struct exception_table_entry *e;
+ int type, reg, imm;
#ifdef CONFIG_PNPBIOS
if (unlikely(SEGMENT_IS_PNP_CODE(regs->cs))) {
@@ -141,7 +167,11 @@ int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code,
if (!e)
return 0;
- switch (e->type) {
+ type = FIELD_GET(EX_DATA_TYPE_MASK, e->data);
+ reg = FIELD_GET(EX_DATA_REG_MASK, e->data);
+ imm = FIELD_GET(EX_DATA_IMM_MASK, e->data);
+
+ switch (type) {
case EX_TYPE_DEFAULT:
case EX_TYPE_DEFAULT_MCE_SAFE:
return ex_handler_default(e, regs);
@@ -170,6 +200,8 @@ int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code,
break;
case EX_TYPE_POP_ZERO:
return ex_handler_pop_zero(e, regs);
+ case EX_TYPE_IMM_REG:
+ return ex_handler_imm_reg(e, regs, reg, imm);
}
BUG();
}
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 726700fabca6..de10dc4d6e1d 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1291,7 +1291,7 @@ st: if (is_imm8(insn->off))
}
ex->insn = delta;
- ex->type = EX_TYPE_BPF;
+ ex->data = EX_TYPE_BPF;
if (dst_reg > BPF_REG_9) {
pr_err("verifier error\n");
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.