aboutsummaryrefslogtreecommitdiff
path: root/arch/arm64/kernel
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm64/kernel')
-rw-r--r--arch/arm64/kernel/hyp-stub.S4
-rw-r--r--arch/arm64/kernel/signal.c83
-rw-r--r--arch/arm64/kernel/stacktrace.c32
3 files changed, 57 insertions, 62 deletions
diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index 65f76064c86b..ae990da1eae5 100644
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -114,8 +114,8 @@ SYM_CODE_START_LOCAL(__finalise_el2)
// Use EL2 translations for SPE & TRBE and disable access from EL1
mrs x0, mdcr_el2
- bic x0, x0, #(MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT)
- bic x0, x0, #(MDCR_EL2_E2TB_MASK << MDCR_EL2_E2TB_SHIFT)
+ bic x0, x0, #MDCR_EL2_E2PB_MASK
+ bic x0, x0, #MDCR_EL2_E2TB_MASK
msr mdcr_el2, x0
// Transfer the MM state from EL1 to EL2
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 14ac6fdb872b..99ea26d400ff 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -36,15 +36,8 @@
#include <asm/traps.h>
#include <asm/vdso.h>
-#ifdef CONFIG_ARM64_GCS
#define GCS_SIGNAL_CAP(addr) (((unsigned long)addr) & GCS_CAP_ADDR_MASK)
-static bool gcs_signal_cap_valid(u64 addr, u64 val)
-{
- return val == GCS_SIGNAL_CAP(addr);
-}
-#endif
-
/*
* Do a signal return; undo the signal stack. These are aligned to 128-bit.
*/
@@ -1062,8 +1055,7 @@ static int restore_sigframe(struct pt_regs *regs,
#ifdef CONFIG_ARM64_GCS
static int gcs_restore_signal(void)
{
- unsigned long __user *gcspr_el0;
- u64 cap;
+ u64 gcspr_el0, cap;
int ret;
if (!system_supports_gcs())
@@ -1072,7 +1064,7 @@ static int gcs_restore_signal(void)
if (!(current->thread.gcs_el0_mode & PR_SHADOW_STACK_ENABLE))
return 0;
- gcspr_el0 = (unsigned long __user *)read_sysreg_s(SYS_GCSPR_EL0);
+ gcspr_el0 = read_sysreg_s(SYS_GCSPR_EL0);
/*
* Ensure that any changes to the GCS done via GCS operations
@@ -1087,22 +1079,23 @@ static int gcs_restore_signal(void)
* then faults will be generated on GCS operations - the main
* concern is to protect GCS pages.
*/
- ret = copy_from_user(&cap, gcspr_el0, sizeof(cap));
+ ret = copy_from_user(&cap, (unsigned long __user *)gcspr_el0,
+ sizeof(cap));
if (ret)
return -EFAULT;
/*
* Check that the cap is the actual GCS before replacing it.
*/
- if (!gcs_signal_cap_valid((u64)gcspr_el0, cap))
+ if (cap != GCS_SIGNAL_CAP(gcspr_el0))
return -EINVAL;
/* Invalidate the token to prevent reuse */
- put_user_gcs(0, (__user void*)gcspr_el0, &ret);
+ put_user_gcs(0, (unsigned long __user *)gcspr_el0, &ret);
if (ret != 0)
return -EFAULT;
- write_sysreg_s(gcspr_el0 + 1, SYS_GCSPR_EL0);
+ write_sysreg_s(gcspr_el0 + 8, SYS_GCSPR_EL0);
return 0;
}
@@ -1421,7 +1414,7 @@ static int get_sigframe(struct rt_sigframe_user_layout *user,
static int gcs_signal_entry(__sigrestore_t sigtramp, struct ksignal *ksig)
{
- unsigned long __user *gcspr_el0;
+ u64 gcspr_el0;
int ret = 0;
if (!system_supports_gcs())
@@ -1434,18 +1427,20 @@ static int gcs_signal_entry(__sigrestore_t sigtramp, struct ksignal *ksig)
* We are entering a signal handler, current register state is
* active.
*/
- gcspr_el0 = (unsigned long __user *)read_sysreg_s(SYS_GCSPR_EL0);
+ gcspr_el0 = read_sysreg_s(SYS_GCSPR_EL0);
/*
* Push a cap and the GCS entry for the trampoline onto the GCS.
*/
- put_user_gcs((unsigned long)sigtramp, gcspr_el0 - 2, &ret);
- put_user_gcs(GCS_SIGNAL_CAP(gcspr_el0 - 1), gcspr_el0 - 1, &ret);
+ put_user_gcs((unsigned long)sigtramp,
+ (unsigned long __user *)(gcspr_el0 - 16), &ret);
+ put_user_gcs(GCS_SIGNAL_CAP(gcspr_el0 - 8),
+ (unsigned long __user *)(gcspr_el0 - 8), &ret);
if (ret != 0)
return ret;
- gcspr_el0 -= 2;
- write_sysreg_s((unsigned long)gcspr_el0, SYS_GCSPR_EL0);
+ gcspr_el0 -= 16;
+ write_sysreg_s(gcspr_el0, SYS_GCSPR_EL0);
return 0;
}
@@ -1462,10 +1457,33 @@ static int setup_return(struct pt_regs *regs, struct ksignal *ksig,
struct rt_sigframe_user_layout *user, int usig)
{
__sigrestore_t sigtramp;
+ int err;
+
+ if (ksig->ka.sa.sa_flags & SA_RESTORER)
+ sigtramp = ksig->ka.sa.sa_restorer;
+ else
+ sigtramp = VDSO_SYMBOL(current->mm->context.vdso, sigtramp);
+
+ err = gcs_signal_entry(sigtramp, ksig);
+ if (err)
+ return err;
+
+ /*
+ * We must not fail from this point onwards. We are going to update
+ * registers, including SP, in order to invoke the signal handler. If
+ * we failed and attempted to deliver a nested SIGSEGV to a handler
+ * after that point, the subsequent sigreturn would end up restoring
+ * the (partial) state for the original signal handler.
+ */
regs->regs[0] = usig;
+ if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
+ regs->regs[1] = (unsigned long)&user->sigframe->info;
+ regs->regs[2] = (unsigned long)&user->sigframe->uc;
+ }
regs->sp = (unsigned long)user->sigframe;
regs->regs[29] = (unsigned long)&user->next_frame->fp;
+ regs->regs[30] = (unsigned long)sigtramp;
regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
/*
@@ -1506,14 +1524,7 @@ static int setup_return(struct pt_regs *regs, struct ksignal *ksig,
sme_smstop();
}
- if (ksig->ka.sa.sa_flags & SA_RESTORER)
- sigtramp = ksig->ka.sa.sa_restorer;
- else
- sigtramp = VDSO_SYMBOL(current->mm->context.vdso, sigtramp);
-
- regs->regs[30] = (unsigned long)sigtramp;
-
- return gcs_signal_entry(sigtramp, ksig);
+ return 0;
}
static int setup_rt_frame(int usig, struct ksignal *ksig, sigset_t *set,
@@ -1537,14 +1548,16 @@ static int setup_rt_frame(int usig, struct ksignal *ksig, sigset_t *set,
err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
err |= setup_sigframe(&user, regs, set, &ua_state);
- if (err == 0) {
+ if (ksig->ka.sa.sa_flags & SA_SIGINFO)
+ err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+
+ if (err == 0)
err = setup_return(regs, ksig, &user, usig);
- if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
- err |= copy_siginfo_to_user(&frame->info, &ksig->info);
- regs->regs[1] = (unsigned long)&frame->info;
- regs->regs[2] = (unsigned long)&frame->uc;
- }
- }
+
+ /*
+ * We must not fail if setup_return() succeeded - see comment at the
+ * beginning of setup_return().
+ */
if (err == 0)
set_handler_user_access_state();
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index caef85462acb..1d9d51d7627f 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -26,7 +26,6 @@ enum kunwind_source {
KUNWIND_SOURCE_CALLER,
KUNWIND_SOURCE_TASK,
KUNWIND_SOURCE_REGS_PC,
- KUNWIND_SOURCE_REGS_LR,
};
union unwind_flags {
@@ -138,8 +137,10 @@ kunwind_recover_return_address(struct kunwind_state *state)
orig_pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
state->common.pc,
(void *)state->common.fp);
- if (WARN_ON_ONCE(state->common.pc == orig_pc))
+ if (state->common.pc == orig_pc) {
+ WARN_ON_ONCE(state->task == current);
return -EINVAL;
+ }
state->common.pc = orig_pc;
state->flags.fgraph = 1;
}
@@ -178,23 +179,8 @@ int kunwind_next_regs_pc(struct kunwind_state *state)
state->regs = regs;
state->common.pc = regs->pc;
state->common.fp = regs->regs[29];
- state->source = KUNWIND_SOURCE_REGS_PC;
- return 0;
-}
-
-static __always_inline int
-kunwind_next_regs_lr(struct kunwind_state *state)
-{
- /*
- * The stack for the regs was consumed by kunwind_next_regs_pc(), so we
- * cannot consume that again here, but we know the regs are safe to
- * access.
- */
- state->common.pc = state->regs->regs[30];
- state->common.fp = state->regs->regs[29];
state->regs = NULL;
- state->source = KUNWIND_SOURCE_REGS_LR;
-
+ state->source = KUNWIND_SOURCE_REGS_PC;
return 0;
}
@@ -215,12 +201,12 @@ kunwind_next_frame_record_meta(struct kunwind_state *state)
case FRAME_META_TYPE_FINAL:
if (meta == &task_pt_regs(tsk)->stackframe)
return -ENOENT;
- WARN_ON_ONCE(1);
+ WARN_ON_ONCE(tsk == current);
return -EINVAL;
case FRAME_META_TYPE_PT_REGS:
return kunwind_next_regs_pc(state);
default:
- WARN_ON_ONCE(1);
+ WARN_ON_ONCE(tsk == current);
return -EINVAL;
}
}
@@ -274,11 +260,8 @@ kunwind_next(struct kunwind_state *state)
case KUNWIND_SOURCE_FRAME:
case KUNWIND_SOURCE_CALLER:
case KUNWIND_SOURCE_TASK:
- case KUNWIND_SOURCE_REGS_LR:
- err = kunwind_next_frame_record(state);
- break;
case KUNWIND_SOURCE_REGS_PC:
- err = kunwind_next_regs_lr(state);
+ err = kunwind_next_frame_record(state);
break;
default:
err = -EINVAL;
@@ -436,7 +419,6 @@ static const char *state_source_string(const struct kunwind_state *state)
case KUNWIND_SOURCE_CALLER: return "C";
case KUNWIND_SOURCE_TASK: return "T";
case KUNWIND_SOURCE_REGS_PC: return "P";
- case KUNWIND_SOURCE_REGS_LR: return "L";
default: return "U";
}
}
Powered by cgit, Gruvboxed by Blaster4385.