Merge branch 'x86/mpx' into x86/asm, to pick up dependent commits

The UMIP series is based on top of changes already queued up in the x86/mpx branch,
so merge it.
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/inat.h

@@ -97,6 +97,16 @@
 #define INAT_MAKE_GROUP(grp)	((grp << INAT_GRP_OFFS) | INAT_MODRM)
 #define INAT_MAKE_IMM(imm)	(imm << INAT_IMM_OFFS)
 
+/* Identifiers for segment registers */
+#define INAT_SEG_REG_IGNORE	0
+#define INAT_SEG_REG_DEFAULT	1
+#define INAT_SEG_REG_CS		2
+#define INAT_SEG_REG_SS		3
+#define INAT_SEG_REG_DS		4
+#define INAT_SEG_REG_ES		5
+#define INAT_SEG_REG_FS		6
+#define INAT_SEG_REG_GS		7
+
 /* Attribute search APIs */
 extern insn_attr_t inat_get_opcode_attribute(insn_byte_t opcode);
 extern int inat_get_last_prefix_id(insn_byte_t last_pfx);

arch/x86/include/asm/insn-eval.h

+#ifndef _ASM_X86_INSN_EVAL_H
+#define _ASM_X86_INSN_EVAL_H
+/*
+ * A collection of utility functions for x86 instruction analysis to be
+ * used in a kernel context. Useful when, for instance, making sense
+ * of the registers indicated by operands.
+ */
+
+#include <linux/compiler.h>
+#include <linux/bug.h>
+#include <linux/err.h>
+#include <asm/ptrace.h>
+
+#define INSN_CODE_SEG_ADDR_SZ(params) ((params >> 4) & 0xf)
+#define INSN_CODE_SEG_OPND_SZ(params) (params & 0xf)
+#define INSN_CODE_SEG_PARAMS(oper_sz, addr_sz) (oper_sz | (addr_sz << 4))
+
+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);
+unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx);
+char insn_get_code_seg_params(struct pt_regs *regs);
+
+#endif /* _ASM_X86_INSN_EVAL_H */

arch/x86/kernel/uprobes.c

@@ -271,12 +271,15 @@ static bool is_prefix_bad(struct insn *insn)
 	int i;
 
 	for (i = 0; i < insn->prefixes.nbytes; i++) {
-		switch (insn->prefixes.bytes[i]) {
-		case 0x26:	/* INAT_PFX_ES   */
-		case 0x2E:	/* INAT_PFX_CS   */
-		case 0x36:	/* INAT_PFX_DS   */
-		case 0x3E:	/* INAT_PFX_SS   */
-		case 0xF0:	/* INAT_PFX_LOCK */
+		insn_attr_t attr;
+
+		attr = inat_get_opcode_attribute(insn->prefixes.bytes[i]);
+		switch (attr) {
+		case INAT_MAKE_PREFIX(INAT_PFX_ES):
+		case INAT_MAKE_PREFIX(INAT_PFX_CS):
+		case INAT_MAKE_PREFIX(INAT_PFX_DS):
+		case INAT_MAKE_PREFIX(INAT_PFX_SS):
+		case INAT_MAKE_PREFIX(INAT_PFX_LOCK):
 			return true;
 		}
 	}

arch/x86/lib/Makefile

@@ -24,7 +24,7 @@ lib-y := delay.o misc.o cmdline.o cpu.o
 lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o
 lib-y += memcpy_$(BITS).o
 lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
-lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o
+lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o
 lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
 
 obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o

arch/x86/mm/mpx.c

@@ -13,6 +13,7 @@
 #include <linux/sched/sysctl.h>
 
 #include <asm/insn.h>
+#include <asm/insn-eval.h>
 #include <asm/mman.h>
 #include <asm/mmu_context.h>
 #include <asm/mpx.h>
@@ -61,123 +62,6 @@ static unsigned long mpx_mmap(unsigned long len)
 	return addr;
 }
 
-enum reg_type {
-	REG_TYPE_RM = 0,
-	REG_TYPE_INDEX,
-	REG_TYPE_BASE,
-};
-
-static int get_reg_offset(struct insn *insn, struct pt_regs *regs,
-			  enum reg_type type)
-{
-	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.
-	 */
-	if (IS_ENABLED(CONFIG_X86_64) && !insn->x86_64)
-		nr_registers -= 8;
-
-	switch (type) {
-	case REG_TYPE_RM:
-		regno = X86_MODRM_RM(insn->modrm.value);
-		if (X86_REX_B(insn->rex_prefix.value))
-			regno += 8;
-		break;
-
-	case REG_TYPE_INDEX:
-		regno = X86_SIB_INDEX(insn->sib.value);
-		if (X86_REX_X(insn->rex_prefix.value))
-			regno += 8;
-		break;
-
-	case REG_TYPE_BASE:
-		regno = X86_SIB_BASE(insn->sib.value);
-		if (X86_REX_B(insn->rex_prefix.value))
-			regno += 8;
-		break;
-
-	default:
-		pr_err("invalid register type");
-		BUG();
-		break;
-	}
-
-	if (regno >= nr_registers) {
-		WARN_ONCE(1, "decoded an instruction with an invalid register");
-		return -EINVAL;
-	}
-	return regoff[regno];
-}
-
-/*
- * return the address being referenced be instruction
- * for rm=3 returning the content of the rm reg
- * for rm!=3 calculates the address using SIB and Disp
- */
-static void __user *mpx_get_addr_ref(struct insn *insn, struct pt_regs *regs)
-{
-	unsigned long addr, base, indx;
-	int addr_offset, base_offset, indx_offset;
-	insn_byte_t sib;
-
-	insn_get_modrm(insn);
-	insn_get_sib(insn);
-	sib = insn->sib.value;
-
-	if (X86_MODRM_MOD(insn->modrm.value) == 3) {
-		addr_offset = get_reg_offset(insn, regs, REG_TYPE_RM);
-		if (addr_offset < 0)
-			goto out_err;
-		addr = regs_get_register(regs, addr_offset);
-	} else {
-		if (insn->sib.nbytes) {
-			base_offset = get_reg_offset(insn, regs, REG_TYPE_BASE);
-			if (base_offset < 0)
-				goto out_err;
-
-			indx_offset = get_reg_offset(insn, regs, REG_TYPE_INDEX);
-			if (indx_offset < 0)
-				goto out_err;
-
-			base = regs_get_register(regs, base_offset);
-			indx = regs_get_register(regs, indx_offset);
-			addr = base + indx * (1 << X86_SIB_SCALE(sib));
-		} else {
-			addr_offset = get_reg_offset(insn, regs, REG_TYPE_RM);
-			if (addr_offset < 0)
-				goto out_err;
-			addr = regs_get_register(regs, addr_offset);
-		}
-		addr += insn->displacement.value;
-	}
-	return (void __user *)addr;
-out_err:
-	return (void __user *)-1;
-}
-
 static int mpx_insn_decode(struct insn *insn,
 			   struct pt_regs *regs)
 {
@@ -290,7 +174,7 @@ siginfo_t *mpx_generate_siginfo(struct pt_regs *regs)
 	info->si_signo = SIGSEGV;
 	info->si_errno = 0;
 	info->si_code = SEGV_BNDERR;
-	info->si_addr = mpx_get_addr_ref(&insn, regs);
+	info->si_addr = insn_get_addr_ref(&insn, regs);
 	/*
 	 * We were not able to extract an address from the instruction,
 	 * probably because there was something invalid in it.