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authorDavid S. Miller <davem@davemloft.net>2018-02-24 00:04:20 -0500
committerDavid S. Miller <davem@davemloft.net>2018-02-24 00:04:20 -0500
commitf74290fdb363665538743d14c4f00aeacdb68d87 (patch)
treea5c8f6332f06550e935d1e557ac927302f7f63c4 /arch/x86
parent1b71af6053af1bd2f849e9fda4f71c1e3f145dcf (diff)
parent9cb9c07d6b0c5fd97d83b8ab14d7e308ba4b612f (diff)
downloadlinux-stericsson-f74290fdb363665538743d14c4f00aeacdb68d87.tar.gz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/include/asm/nospec-branch.h37
-rw-r--r--arch/x86/kernel/machine_kexec_64.c1
-rw-r--r--arch/x86/kernel/module.c1
-rw-r--r--arch/x86/net/bpf_jit_comp.c9
-rw-r--r--arch/x86/tools/relocs.c3
5 files changed, 47 insertions, 4 deletions
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 76b058533e47..81a1be326571 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -177,4 +177,41 @@ static inline void indirect_branch_prediction_barrier(void)
}
#endif /* __ASSEMBLY__ */
+
+/*
+ * Below is used in the eBPF JIT compiler and emits the byte sequence
+ * for the following assembly:
+ *
+ * With retpolines configured:
+ *
+ * callq do_rop
+ * spec_trap:
+ * pause
+ * lfence
+ * jmp spec_trap
+ * do_rop:
+ * mov %rax,(%rsp)
+ * retq
+ *
+ * Without retpolines configured:
+ *
+ * jmp *%rax
+ */
+#ifdef CONFIG_RETPOLINE
+# define RETPOLINE_RAX_BPF_JIT_SIZE 17
+# define RETPOLINE_RAX_BPF_JIT() \
+ EMIT1_off32(0xE8, 7); /* callq do_rop */ \
+ /* spec_trap: */ \
+ EMIT2(0xF3, 0x90); /* pause */ \
+ EMIT3(0x0F, 0xAE, 0xE8); /* lfence */ \
+ EMIT2(0xEB, 0xF9); /* jmp spec_trap */ \
+ /* do_rop: */ \
+ EMIT4(0x48, 0x89, 0x04, 0x24); /* mov %rax,(%rsp) */ \
+ EMIT1(0xC3); /* retq */
+#else
+# define RETPOLINE_RAX_BPF_JIT_SIZE 2
+# define RETPOLINE_RAX_BPF_JIT() \
+ EMIT2(0xFF, 0xE0); /* jmp *%rax */
+#endif
+
#endif /* _ASM_X86_NOSPEC_BRANCH_H_ */
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 1f790cf9d38f..3b7427aa7d85 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -542,6 +542,7 @@ int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr,
goto overflow;
break;
case R_X86_64_PC32:
+ case R_X86_64_PLT32:
value -= (u64)address;
*(u32 *)location = value;
break;
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index da0c160e5589..f58336af095c 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -191,6 +191,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
goto overflow;
break;
case R_X86_64_PC32:
+ case R_X86_64_PLT32:
if (*(u32 *)loc != 0)
goto invalid_relocation;
val -= (u64)loc;
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 4923d92f918d..45e4eb5bcbb2 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -13,6 +13,7 @@
#include <linux/if_vlan.h>
#include <asm/cacheflush.h>
#include <asm/set_memory.h>
+#include <asm/nospec-branch.h>
#include <linux/bpf.h>
/*
@@ -290,7 +291,7 @@ static void emit_bpf_tail_call(u8 **pprog)
EMIT2(0x89, 0xD2); /* mov edx, edx */
EMIT3(0x39, 0x56, /* cmp dword ptr [rsi + 16], edx */
offsetof(struct bpf_array, map.max_entries));
-#define OFFSET1 43 /* number of bytes to jump */
+#define OFFSET1 (41 + RETPOLINE_RAX_BPF_JIT_SIZE) /* number of bytes to jump */
EMIT2(X86_JBE, OFFSET1); /* jbe out */
label1 = cnt;
@@ -299,7 +300,7 @@ static void emit_bpf_tail_call(u8 **pprog)
*/
EMIT2_off32(0x8B, 0x85, 36); /* mov eax, dword ptr [rbp + 36] */
EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
-#define OFFSET2 32
+#define OFFSET2 (30 + RETPOLINE_RAX_BPF_JIT_SIZE)
EMIT2(X86_JA, OFFSET2); /* ja out */
label2 = cnt;
EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
@@ -313,7 +314,7 @@ static void emit_bpf_tail_call(u8 **pprog)
* goto out;
*/
EMIT3(0x48, 0x85, 0xC0); /* test rax,rax */
-#define OFFSET3 10
+#define OFFSET3 (8 + RETPOLINE_RAX_BPF_JIT_SIZE)
EMIT2(X86_JE, OFFSET3); /* je out */
label3 = cnt;
@@ -326,7 +327,7 @@ static void emit_bpf_tail_call(u8 **pprog)
* rdi == ctx (1st arg)
* rax == prog->bpf_func + prologue_size
*/
- EMIT2(0xFF, 0xE0); /* jmp rax */
+ RETPOLINE_RAX_BPF_JIT();
/* out: */
BUILD_BUG_ON(cnt - label1 != OFFSET1);
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 5d73c443e778..220e97841e49 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -770,9 +770,12 @@ static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
break;
case R_X86_64_PC32:
+ case R_X86_64_PLT32:
/*
* PC relative relocations don't need to be adjusted unless
* referencing a percpu symbol.
+ *
+ * NB: R_X86_64_PLT32 can be treated as R_X86_64_PC32.
*/
if (is_percpu_sym(sym, symname))
add_reloc(&relocs32neg, offset);