arm64: Defer enabling pointer authentication on boot core

Defer enabling pointer authentication on boot core until
after its required to be enabled by cpufeature framework.
This will help in controlling the feature dynamically
with a boot parameter.

Signed-off-by: Ajay Patil <pajay@qti.qualcomm.com>
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
Signed-off-by: Srinivas Ramana <sramana@codeaurora.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1610152163-16554-2-git-send-email-sramana@codeaurora.org
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: David Brazdil <dbrazdil@google.com>
Link: https://lore.kernel.org/r/20210208095732.3267263-22-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/include/asm/pointer_auth.h b/arch/arm64/include/asm/pointer_auth.h
index c6b4f0603024332948677b9ec9606d201ac32b28..b112a11e93024f4cff245b294fdf48637cd01f6d 100644 (file)
--- a/arch/arm64/include/asm/pointer_auth.h
+++ b/arch/arm64/include/asm/pointer_auth.h
@@ -76,6 +76,15 @@ static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr)
        return ptrauth_clear_pac(ptr);
 }
 
+static __always_inline void ptrauth_enable(void)
+{
+       if (!system_supports_address_auth())
+               return;
+       sysreg_clear_set(sctlr_el1, 0, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB |
+                                       SCTLR_ELx_ENDA | SCTLR_ELx_ENDB));
+       isb();
+}
+
 #define ptrauth_thread_init_user(tsk)                                  \
        ptrauth_keys_init_user(&(tsk)->thread.keys_user)
 #define ptrauth_thread_init_kernel(tsk)                                        \
@@ -84,6 +93,7 @@ static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr)
        ptrauth_keys_switch_kernel(&(tsk)->thread.keys_kernel)
 
 #else /* CONFIG_ARM64_PTR_AUTH */
+#define ptrauth_enable()
 #define ptrauth_prctl_reset_keys(tsk, arg)     (-EINVAL)
 #define ptrauth_strip_insn_pac(lr)     (lr)
 #define ptrauth_thread_init_user(tsk)

diff --git a/arch/arm64/include/asm/stackprotector.h b/arch/arm64/include/asm/stackprotector.h
index 7263e0bac680789cfa244802a2c72fd24c0a3fa3..33f1bb4531509ceb6665d98488892f6da30ddac6 100644 (file)
--- a/arch/arm64/include/asm/stackprotector.h
+++ b/arch/arm64/include/asm/stackprotector.h
@@ -41,6 +41,7 @@ static __always_inline void boot_init_stack_canary(void)
 #endif
        ptrauth_thread_init_kernel(current);
        ptrauth_thread_switch_kernel(current);
+       ptrauth_enable();
 }
 
 #endif /* _ASM_STACKPROTECTOR_H */

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index e7f12bf497308a3d5874b4d462e74b2a097c9802..1e30b5550d2a76696a00dfeddedaeb4b32769f6a 100644 (file)
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -404,10 +404,6 @@ SYM_FUNC_START_LOCAL(__primary_switched)
        adr_l   x5, init_task
        msr     sp_el0, x5                      // Save thread_info
 
-#ifdef CONFIG_ARM64_PTR_AUTH
-       __ptrauth_keys_init_cpu x5, x6, x7, x8
-#endif
-
        adr_l   x8, vectors                     // load VBAR_EL1 with virtual
        msr     vbar_el1, x8                    // vector table address
        isb