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-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/x86/include/asm/error-injection.h13
-rw-r--r--arch/x86/include/asm/kprobes.h2
-rw-r--r--arch/x86/include/asm/ptrace.h5
-rw-r--r--arch/x86/lib/Makefile1
-rw-r--r--arch/x86/lib/error-inject.c19
-rw-r--r--arch/x86/net/bpf_jit_comp.c106
7 files changed, 116 insertions, 31 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index dbe5542a6666..fcd3b4d24eea 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -155,6 +155,7 @@ config X86
select HAVE_KERNEL_XZ
select HAVE_KPROBES
select HAVE_KPROBES_ON_FTRACE
+ select HAVE_FUNCTION_ERROR_INJECTION
select HAVE_KRETPROBES
select HAVE_KVM
select HAVE_LIVEPATCH if X86_64
diff --git a/arch/x86/include/asm/error-injection.h b/arch/x86/include/asm/error-injection.h
new file mode 100644
index 000000000000..47b7a1296245
--- /dev/null
+++ b/arch/x86/include/asm/error-injection.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_ERROR_INJECTION_H
+#define _ASM_ERROR_INJECTION_H
+
+#include <linux/compiler.h>
+#include <linux/linkage.h>
+#include <asm/ptrace.h>
+#include <asm-generic/error-injection.h>
+
+asmlinkage void just_return_func(void);
+void override_function_with_return(struct pt_regs *regs);
+
+#endif /* _ASM_ERROR_INJECTION_H */
diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h
index 9f2e3102e0bb..367d99cff426 100644
--- a/arch/x86/include/asm/kprobes.h
+++ b/arch/x86/include/asm/kprobes.h
@@ -67,6 +67,8 @@ extern const int kretprobe_blacklist_size;
void arch_remove_kprobe(struct kprobe *p);
asmlinkage void kretprobe_trampoline(void);
+extern void arch_kprobe_override_function(struct pt_regs *regs);
+
/* Architecture specific copy of original instruction*/
struct arch_specific_insn {
/* copy of the original instruction */
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 14131dd06b29..6de1fd3d0097 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -109,6 +109,11 @@ static inline unsigned long regs_return_value(struct pt_regs *regs)
return regs->ax;
}
+static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
+{
+ regs->ax = rc;
+}
+
/*
* user_mode(regs) determines whether a register set came from user
* mode. On x86_32, this is true if V8086 mode was enabled OR if the
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 69a473919260..91e9700cc6dc 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -26,6 +26,7 @@ lib-y += memcpy_$(BITS).o
lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o
lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
+lib-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
lib-$(CONFIG_RETPOLINE) += retpoline.o
OBJECT_FILES_NON_STANDARD_retpoline.o :=y
diff --git a/arch/x86/lib/error-inject.c b/arch/x86/lib/error-inject.c
new file mode 100644
index 000000000000..7b881d03d0dd
--- /dev/null
+++ b/arch/x86/lib/error-inject.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/error-injection.h>
+#include <linux/kprobes.h>
+
+asmlinkage void just_return_func(void);
+
+asm(
+ ".type just_return_func, @function\n"
+ "just_return_func:\n"
+ " ret\n"
+ ".size just_return_func, .-just_return_func\n"
+);
+
+void override_function_with_return(struct pt_regs *regs)
+{
+ regs->ip = (unsigned long)&just_return_func;
+}
+NOKPROBE_SYMBOL(override_function_with_return);
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 0554e8aef4d5..4923d92f918d 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -15,8 +15,6 @@
#include <asm/set_memory.h>
#include <linux/bpf.h>
-int bpf_jit_enable __read_mostly;
-
/*
* assembly code in arch/x86/net/bpf_jit.S
*/
@@ -154,6 +152,11 @@ static bool is_ereg(u32 reg)
BIT(BPF_REG_AX));
}
+static bool is_axreg(u32 reg)
+{
+ return reg == BPF_REG_0;
+}
+
/* add modifiers if 'reg' maps to x64 registers r8..r15 */
static u8 add_1mod(u8 byte, u32 reg)
{
@@ -447,16 +450,36 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
else if (is_ereg(dst_reg))
EMIT1(add_1mod(0x40, dst_reg));
+ /* b3 holds 'normal' opcode, b2 short form only valid
+ * in case dst is eax/rax.
+ */
switch (BPF_OP(insn->code)) {
- case BPF_ADD: b3 = 0xC0; break;
- case BPF_SUB: b3 = 0xE8; break;
- case BPF_AND: b3 = 0xE0; break;
- case BPF_OR: b3 = 0xC8; break;
- case BPF_XOR: b3 = 0xF0; break;
+ case BPF_ADD:
+ b3 = 0xC0;
+ b2 = 0x05;
+ break;
+ case BPF_SUB:
+ b3 = 0xE8;
+ b2 = 0x2D;
+ break;
+ case BPF_AND:
+ b3 = 0xE0;
+ b2 = 0x25;
+ break;
+ case BPF_OR:
+ b3 = 0xC8;
+ b2 = 0x0D;
+ break;
+ case BPF_XOR:
+ b3 = 0xF0;
+ b2 = 0x35;
+ break;
}
if (is_imm8(imm32))
EMIT3(0x83, add_1reg(b3, dst_reg), imm32);
+ else if (is_axreg(dst_reg))
+ EMIT1_off32(b2, imm32);
else
EMIT2_off32(0x81, add_1reg(b3, dst_reg), imm32);
break;
@@ -545,26 +568,6 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
*/
EMIT2(0x31, 0xd2);
- if (BPF_SRC(insn->code) == BPF_X) {
- /* if (src_reg == 0) return 0 */
-
- /* cmp r11, 0 */
- EMIT4(0x49, 0x83, 0xFB, 0x00);
-
- /* jne .+9 (skip over pop, pop, xor and jmp) */
- EMIT2(X86_JNE, 1 + 1 + 2 + 5);
- EMIT1(0x5A); /* pop rdx */
- EMIT1(0x58); /* pop rax */
- EMIT2(0x31, 0xc0); /* xor eax, eax */
-
- /* jmp cleanup_addr
- * addrs[i] - 11, because there are 11 bytes
- * after this insn: div, mov, pop, pop, mov
- */
- jmp_offset = ctx->cleanup_addr - (addrs[i] - 11);
- EMIT1_off32(0xE9, jmp_offset);
- }
-
if (BPF_CLASS(insn->code) == BPF_ALU64)
/* div r11 */
EMIT3(0x49, 0xF7, 0xF3);
@@ -1109,19 +1112,29 @@ common_load:
return proglen;
}
+struct x64_jit_data {
+ struct bpf_binary_header *header;
+ int *addrs;
+ u8 *image;
+ int proglen;
+ struct jit_context ctx;
+};
+
struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
{
struct bpf_binary_header *header = NULL;
struct bpf_prog *tmp, *orig_prog = prog;
+ struct x64_jit_data *jit_data;
int proglen, oldproglen = 0;
struct jit_context ctx = {};
bool tmp_blinded = false;
+ bool extra_pass = false;
u8 *image = NULL;
int *addrs;
int pass;
int i;
- if (!bpf_jit_enable)
+ if (!prog->jit_requested)
return orig_prog;
tmp = bpf_jit_blind_constants(prog);
@@ -1135,10 +1148,28 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
prog = tmp;
}
+ jit_data = prog->aux->jit_data;
+ if (!jit_data) {
+ jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
+ if (!jit_data) {
+ prog = orig_prog;
+ goto out;
+ }
+ prog->aux->jit_data = jit_data;
+ }
+ addrs = jit_data->addrs;
+ if (addrs) {
+ ctx = jit_data->ctx;
+ oldproglen = jit_data->proglen;
+ image = jit_data->image;
+ header = jit_data->header;
+ extra_pass = true;
+ goto skip_init_addrs;
+ }
addrs = kmalloc(prog->len * sizeof(*addrs), GFP_KERNEL);
if (!addrs) {
prog = orig_prog;
- goto out;
+ goto out_addrs;
}
/* Before first pass, make a rough estimation of addrs[]
@@ -1149,6 +1180,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
addrs[i] = proglen;
}
ctx.cleanup_addr = proglen;
+skip_init_addrs:
/* JITed image shrinks with every pass and the loop iterates
* until the image stops shrinking. Very large bpf programs
@@ -1189,7 +1221,15 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
if (image) {
bpf_flush_icache(header, image + proglen);
- bpf_jit_binary_lock_ro(header);
+ if (!prog->is_func || extra_pass) {
+ bpf_jit_binary_lock_ro(header);
+ } else {
+ jit_data->addrs = addrs;
+ jit_data->ctx = ctx;
+ jit_data->proglen = proglen;
+ jit_data->image = image;
+ jit_data->header = header;
+ }
prog->bpf_func = (void *)image;
prog->jited = 1;
prog->jited_len = proglen;
@@ -1197,8 +1237,12 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
prog = orig_prog;
}
+ if (!prog->is_func || extra_pass) {
out_addrs:
- kfree(addrs);
+ kfree(addrs);
+ kfree(jit_data);
+ prog->aux->jit_data = NULL;
+ }
out:
if (tmp_blinded)
bpf_jit_prog_release_other(prog, prog == orig_prog ?
generated by cgit v1.2.3-70-g09d2 (git 2.47.1) at 2024-12-28 19:07:44 +0000