| Message ID | 20190125225714.10234-6-richard.henderson@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | target/arm: Complete ARMv8.3-PAuth linux-user | expand |
On Fri, 25 Jan 2019 at 22:57, Richard Henderson <richard.henderson@linaro.org> wrote: > > Initialize the keys to a non-zero value on process start. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > +static uint64_t arm_rand64(void) > +{ > + int shift = 64 - clz64(RAND_MAX); > + int i, n = 64 / shift + (64 % shift != 0); > + uint64_t ret = 0; > + > + for (i = 0; i < n; i++) { > + ret = (ret << shift) | rand(); > + } > + return ret; > +} I'm not a huge fan of the use of rand() here, but it's what we're using to initialize AT_RANDOM in linux-user, so I guess it's OK here. At some point we should investigate whether there's something better we are guaranteed to have available, I suppose. (Coverity gripes about use of rand().) thanks -- PMM
On 2/1/19 7:11 AM, Peter Maydell wrote: > On Fri, 25 Jan 2019 at 22:57, Richard Henderson > <richard.henderson@linaro.org> wrote: >> >> Initialize the keys to a non-zero value on process start. >> >> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > >> +static uint64_t arm_rand64(void) >> +{ >> + int shift = 64 - clz64(RAND_MAX); >> + int i, n = 64 / shift + (64 % shift != 0); >> + uint64_t ret = 0; >> + >> + for (i = 0; i < n; i++) { >> + ret = (ret << shift) | rand(); >> + } >> + return ret; >> +} > > I'm not a huge fan of the use of rand() here, but it's what > we're using to initialize AT_RANDOM in linux-user, so I guess > it's OK here. At some point we should investigate whether > there's something better we are guaranteed to have available, > I suppose. (Coverity gripes about use of rand().) I considered implementing a qemu version of getentropy, but then I saw our "-seed" option and thought perhaps repeatability is more important for qemu. r~
diff --git a/linux-user/aarch64/target_syscall.h b/linux-user/aarch64/target_syscall.h index 205265e619..937fd7989e 100644 --- a/linux-user/aarch64/target_syscall.h +++ b/linux-user/aarch64/target_syscall.h @@ -22,4 +22,6 @@ struct target_pt_regs { #define TARGET_PR_SVE_SET_VL 50 #define TARGET_PR_SVE_GET_VL 51 +void arm_init_pauth_key(ARMPACKey *key); + #endif /* AARCH64_TARGET_SYSCALL_H */ diff --git a/linux-user/aarch64/cpu_loop.c b/linux-user/aarch64/cpu_loop.c index 65d815f030..d75fd9d3e2 100644 --- a/linux-user/aarch64/cpu_loop.c +++ b/linux-user/aarch64/cpu_loop.c @@ -147,10 +147,29 @@ void cpu_loop(CPUARMState *env) } } +static uint64_t arm_rand64(void) +{ + int shift = 64 - clz64(RAND_MAX); + int i, n = 64 / shift + (64 % shift != 0); + uint64_t ret = 0; + + for (i = 0; i < n; i++) { + ret = (ret << shift) | rand(); + } + return ret; +} + +void arm_init_pauth_key(ARMPACKey *key) +{ + key->lo = arm_rand64(); + key->hi = arm_rand64(); +} + void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs) { - CPUState *cpu = ENV_GET_CPU(env); - TaskState *ts = cpu->opaque; + ARMCPU *cpu = arm_env_get_cpu(env); + CPUState *cs = CPU(cpu); + TaskState *ts = cs->opaque; struct image_info *info = ts->info; int i; @@ -172,6 +191,14 @@ void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs) } #endif + if (cpu_isar_feature(aa64_pauth, cpu)) { + arm_init_pauth_key(&env->apia_key); + arm_init_pauth_key(&env->apib_key); + arm_init_pauth_key(&env->apda_key); + arm_init_pauth_key(&env->apdb_key); + arm_init_pauth_key(&env->apga_key); + } + ts->stack_base = info->start_stack; ts->heap_base = info->brk; /* This will be filled in on the first SYS_HEAPINFO call. */
Initialize the keys to a non-zero value on process start. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- linux-user/aarch64/target_syscall.h | 2 ++ linux-user/aarch64/cpu_loop.c | 31 +++++++++++++++++++++++++++-- 2 files changed, 31 insertions(+), 2 deletions(-) -- 2.17.2