diff options
Diffstat (limited to 'tools/testing/selftests/rseq/rseq-arm.h')
-rw-r--r-- | tools/testing/selftests/rseq/rseq-arm.h | 132 |
1 files changed, 118 insertions, 14 deletions
diff --git a/tools/testing/selftests/rseq/rseq-arm.h b/tools/testing/selftests/rseq/rseq-arm.h index 3cea19877227..84f28f147fb6 100644 --- a/tools/testing/selftests/rseq/rseq-arm.h +++ b/tools/testing/selftests/rseq/rseq-arm.h @@ -5,7 +5,54 @@ * (C) Copyright 2016-2018 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> */ -#define RSEQ_SIG 0x53053053 +/* + * RSEQ_SIG uses the udf A32 instruction with an uncommon immediate operand + * value 0x5de3. This traps if user-space reaches this instruction by mistake, + * and the uncommon operand ensures the kernel does not move the instruction + * pointer to attacker-controlled code on rseq abort. + * + * The instruction pattern in the A32 instruction set is: + * + * e7f5def3 udf #24035 ; 0x5de3 + * + * This translates to the following instruction pattern in the T16 instruction + * set: + * + * little endian: + * def3 udf #243 ; 0xf3 + * e7f5 b.n <7f5> + * + * pre-ARMv6 big endian code: + * e7f5 b.n <7f5> + * def3 udf #243 ; 0xf3 + * + * ARMv6+ -mbig-endian generates mixed endianness code vs data: little-endian + * code and big-endian data. Ensure the RSEQ_SIG data signature matches code + * endianness. Prior to ARMv6, -mbig-endian generates big-endian code and data + * (which match), so there is no need to reverse the endianness of the data + * representation of the signature. However, the choice between BE32 and BE8 + * is done by the linker, so we cannot know whether code and data endianness + * will be mixed before the linker is invoked. + */ + +#define RSEQ_SIG_CODE 0xe7f5def3 + +#ifndef __ASSEMBLER__ + +#define RSEQ_SIG_DATA \ + ({ \ + int sig; \ + asm volatile ("b 2f\n\t" \ + "1: .inst " __rseq_str(RSEQ_SIG_CODE) "\n\t" \ + "2:\n\t" \ + "ldr %[sig], 1b\n\t" \ + : [sig] "=r" (sig)); \ + sig; \ + }) + +#define RSEQ_SIG RSEQ_SIG_DATA + +#endif #define rseq_smp_mb() __asm__ __volatile__ ("dmb" ::: "memory", "cc") #define rseq_smp_rmb() __asm__ __volatile__ ("dmb" ::: "memory", "cc") @@ -30,18 +77,35 @@ do { \ #include "rseq-skip.h" #else /* !RSEQ_SKIP_FASTPATH */ -#define __RSEQ_ASM_DEFINE_TABLE(version, flags, start_ip, \ +#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, start_ip, \ post_commit_offset, abort_ip) \ - ".pushsection __rseq_table, \"aw\"\n\t" \ + ".pushsection __rseq_cs, \"aw\"\n\t" \ ".balign 32\n\t" \ + __rseq_str(label) ":\n\t" \ ".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \ ".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \ + ".popsection\n\t" \ + ".pushsection __rseq_cs_ptr_array, \"aw\"\n\t" \ + ".word " __rseq_str(label) "b, 0x0\n\t" \ ".popsection\n\t" -#define RSEQ_ASM_DEFINE_TABLE(start_ip, post_commit_ip, abort_ip) \ - __RSEQ_ASM_DEFINE_TABLE(0x0, 0x0, start_ip, \ +#define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \ + __RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip, \ (post_commit_ip - start_ip), abort_ip) +/* + * Exit points of a rseq critical section consist of all instructions outside + * of the critical section where a critical section can either branch to or + * reach through the normal course of its execution. The abort IP and the + * post-commit IP are already part of the __rseq_cs section and should not be + * explicitly defined as additional exit points. Knowing all exit points is + * useful to assist debuggers stepping over the critical section. + */ +#define RSEQ_ASM_DEFINE_EXIT_POINT(start_ip, exit_ip) \ + ".pushsection __rseq_exit_point_array, \"aw\"\n\t" \ + ".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(exit_ip) ", 0x0\n\t" \ + ".popsection\n\t" + #define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs) \ RSEQ_INJECT_ASM(1) \ "adr r0, " __rseq_str(cs_label) "\n\t" \ @@ -61,7 +125,8 @@ do { \ __rseq_str(table_label) ":\n\t" \ ".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \ ".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \ - ".word " __rseq_str(RSEQ_SIG) "\n\t" \ + ".arm\n\t" \ + ".inst " __rseq_str(RSEQ_SIG_CODE) "\n\t" \ __rseq_str(label) ":\n\t" \ teardown \ "b %l[" __rseq_str(abort_label) "]\n\t" @@ -86,7 +151,12 @@ int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, int cpu) rseq_workaround_gcc_asm_size_guess(); __asm__ __volatile__ goto ( - RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail]) +#ifdef RSEQ_COMPARE_TWICE + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1]) + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2]) +#endif /* Start rseq by storing table entry pointer into rseq_cs. */ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs) RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f) @@ -148,7 +218,12 @@ int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot, rseq_workaround_gcc_asm_size_guess(); __asm__ __volatile__ goto ( - RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail]) +#ifdef RSEQ_COMPARE_TWICE + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1]) + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2]) +#endif /* Start rseq by storing table entry pointer into rseq_cs. */ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs) RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f) @@ -214,7 +289,10 @@ int rseq_addv(intptr_t *v, intptr_t count, int cpu) rseq_workaround_gcc_asm_size_guess(); __asm__ __volatile__ goto ( - RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */ +#ifdef RSEQ_COMPARE_TWICE + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1]) +#endif /* Start rseq by storing table entry pointer into rseq_cs. */ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs) RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f) @@ -266,7 +344,12 @@ int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect, rseq_workaround_gcc_asm_size_guess(); __asm__ __volatile__ goto ( - RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail]) +#ifdef RSEQ_COMPARE_TWICE + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1]) + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2]) +#endif /* Start rseq by storing table entry pointer into rseq_cs. */ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs) RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f) @@ -336,7 +419,12 @@ int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect, rseq_workaround_gcc_asm_size_guess(); __asm__ __volatile__ goto ( - RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail]) +#ifdef RSEQ_COMPARE_TWICE + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1]) + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2]) +#endif /* Start rseq by storing table entry pointer into rseq_cs. */ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs) RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f) @@ -407,7 +495,13 @@ int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect, rseq_workaround_gcc_asm_size_guess(); __asm__ __volatile__ goto ( - RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail]) +#ifdef RSEQ_COMPARE_TWICE + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1]) + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2]) + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error3]) +#endif /* Start rseq by storing table entry pointer into rseq_cs. */ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs) RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f) @@ -485,7 +579,12 @@ int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect, rseq_workaround_gcc_asm_size_guess(); __asm__ __volatile__ goto ( - RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail]) +#ifdef RSEQ_COMPARE_TWICE + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1]) + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2]) +#endif "str %[src], %[rseq_scratch0]\n\t" "str %[dst], %[rseq_scratch1]\n\t" "str %[len], %[rseq_scratch2]\n\t" @@ -604,7 +703,12 @@ int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect, rseq_workaround_gcc_asm_size_guess(); __asm__ __volatile__ goto ( - RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_TABLE(9, 1f, 2f, 4f) /* start, commit, abort */ + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[cmpfail]) +#ifdef RSEQ_COMPARE_TWICE + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error1]) + RSEQ_ASM_DEFINE_EXIT_POINT(1f, %l[error2]) +#endif "str %[src], %[rseq_scratch0]\n\t" "str %[dst], %[rseq_scratch1]\n\t" "str %[len], %[rseq_scratch2]\n\t" |