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-rw-r--r--arch/arm64/include/asm/pointer_auth.h79
-rw-r--r--arch/arm64/include/asm/thread_info.h4
-rw-r--r--arch/arm64/include/uapi/asm/hwcap.h2
-rw-r--r--arch/arm64/kernel/cpufeature.c13
-rw-r--r--arch/arm64/kernel/cpuinfo.c2
-rw-r--r--arch/arm64/kernel/process.c4
6 files changed, 104 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/pointer_auth.h b/arch/arm64/include/asm/pointer_auth.h
new file mode 100644
index 000000000000..91c4185dda5b
--- /dev/null
+++ b/arch/arm64/include/asm/pointer_auth.h
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef __ASM_POINTER_AUTH_H
+#define __ASM_POINTER_AUTH_H
+
+#include <linux/random.h>
+
+#include <asm/cpufeature.h>
+#include <asm/sysreg.h>
+
+#ifdef CONFIG_ARM64_PTR_AUTH
+/*
+ * Each key is a 128-bit quantity which is split across a pair of 64-bit
+ * registers (Lo and Hi).
+ */
+struct ptrauth_key {
+ unsigned long lo, hi;
+};
+
+/*
+ * We give each process its own keys, which are shared by all threads. The keys
+ * are inherited upon fork(), and reinitialised upon exec*().
+ */
+struct ptrauth_keys {
+ struct ptrauth_key apia;
+ struct ptrauth_key apib;
+ struct ptrauth_key apda;
+ struct ptrauth_key apdb;
+ struct ptrauth_key apga;
+};
+
+static inline void ptrauth_keys_init(struct ptrauth_keys *keys)
+{
+ if (system_supports_address_auth()) {
+ get_random_bytes(&keys->apia, sizeof(keys->apia));
+ get_random_bytes(&keys->apib, sizeof(keys->apib));
+ get_random_bytes(&keys->apda, sizeof(keys->apda));
+ get_random_bytes(&keys->apdb, sizeof(keys->apdb));
+ }
+
+ if (system_supports_generic_auth())
+ get_random_bytes(&keys->apga, sizeof(keys->apga));
+}
+
+#define __ptrauth_key_install(k, v) \
+do { \
+ struct ptrauth_key __pki_v = (v); \
+ write_sysreg_s(__pki_v.lo, SYS_ ## k ## KEYLO_EL1); \
+ write_sysreg_s(__pki_v.hi, SYS_ ## k ## KEYHI_EL1); \
+} while (0)
+
+static inline void ptrauth_keys_switch(struct ptrauth_keys *keys)
+{
+ if (system_supports_address_auth()) {
+ __ptrauth_key_install(APIA, keys->apia);
+ __ptrauth_key_install(APIB, keys->apib);
+ __ptrauth_key_install(APDA, keys->apda);
+ __ptrauth_key_install(APDB, keys->apdb);
+ }
+
+ if (system_supports_generic_auth())
+ __ptrauth_key_install(APGA, keys->apga);
+}
+
+#define ptrauth_thread_init_user(tsk) \
+do { \
+ struct task_struct *__ptiu_tsk = (tsk); \
+ ptrauth_keys_init(&__ptiu_tsk->thread_info.keys_user); \
+ ptrauth_keys_switch(&__ptiu_tsk->thread_info.keys_user); \
+} while (0)
+
+#define ptrauth_thread_switch(tsk) \
+ ptrauth_keys_switch(&(tsk)->thread_info.keys_user)
+
+#else /* CONFIG_ARM64_PTR_AUTH */
+#define ptrauth_thread_init_user(tsk)
+#define ptrauth_thread_switch(tsk)
+#endif /* CONFIG_ARM64_PTR_AUTH */
+
+#endif /* __ASM_POINTER_AUTH_H */
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index bbca68b54732..f8f66ad9dd8f 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -28,6 +28,7 @@
struct task_struct;
#include <asm/memory.h>
+#include <asm/pointer_auth.h>
#include <asm/stack_pointer.h>
#include <asm/types.h>
@@ -54,6 +55,9 @@ struct thread_info {
#endif
} preempt;
};
+#ifdef CONFIG_ARM64_PTR_AUTH
+ struct ptrauth_keys keys_user;
+#endif
};
#define thread_saved_pc(tsk) \
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index 7784f7cba16c..5f0750c2199c 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -50,5 +50,7 @@
#define HWCAP_FLAGM (1 << 27)
#define HWCAP_SSBS (1 << 28)
#define HWCAP_SB (1 << 29)
+#define HWCAP_PACA (1 << 30)
+#define HWCAP_PACG (1UL << 31)
#endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index c82ebd8f0087..f15000872e08 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1191,6 +1191,12 @@ static void cpu_clear_disr(const struct arm64_cpu_capabilities *__unused)
#endif /* CONFIG_ARM64_RAS_EXTN */
#ifdef CONFIG_ARM64_PTR_AUTH
+static void cpu_enable_address_auth(struct arm64_cpu_capabilities const *cap)
+{
+ sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_ENIA | SCTLR_ELx_ENIB |
+ SCTLR_ELx_ENDA | SCTLR_ELx_ENDB);
+}
+
static bool has_address_auth(const struct arm64_cpu_capabilities *entry,
int __unused)
{
@@ -1478,6 +1484,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.capability = ARM64_HAS_ADDRESS_AUTH,
.type = ARM64_CPUCAP_SYSTEM_FEATURE,
.matches = has_address_auth,
+ .cpu_enable = cpu_enable_address_auth,
},
{
.desc = "Generic authentication (architected algorithm)",
@@ -1552,6 +1559,12 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_SVE_SHIFT, FTR_UNSIGNED, ID_AA64PFR0_SVE, CAP_HWCAP, HWCAP_SVE),
#endif
HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_SSBS_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_SSBS_PSTATE_INSNS, CAP_HWCAP, HWCAP_SSBS),
+#ifdef CONFIG_ARM64_PTR_AUTH
+ { .desc = "HWCAP_PACA", .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_address_auth,
+ .hwcap_type = CAP_HWCAP, .hwcap = HWCAP_PACA },
+ { .desc = "HWCAP_PACG", .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_generic_auth,
+ .hwcap_type = CAP_HWCAP, .hwcap = HWCAP_PACG },
+#endif
{},
};
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 7cb0b08ab0a7..ca0685f33900 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -83,6 +83,8 @@ static const char *const hwcap_str[] = {
"flagm",
"ssbs",
"sb",
+ "paca",
+ "pacg",
NULL
};
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 8a2d68f04e0d..e0a443730e04 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -57,6 +57,7 @@
#include <asm/fpsimd.h>
#include <asm/mmu_context.h>
#include <asm/processor.h>
+#include <asm/pointer_auth.h>
#include <asm/stacktrace.h>
#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
@@ -429,6 +430,7 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
contextidr_thread_switch(next);
entry_task_switch(next);
uao_thread_switch(next);
+ ptrauth_thread_switch(next);
/*
* Complete any pending TLB or cache maintenance on this CPU in case
@@ -496,4 +498,6 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
void arch_setup_new_exec(void)
{
current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0;
+
+ ptrauth_thread_init_user(current);
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-22 15:25:44 +0000