From: Mark Rutland <[email protected]>

This will mean we do more work per EL0 exception return, but is a
stepping-stone to enable keys within the kernel.

Signed-off-by: Mark Rutland <[email protected]>
Signed-off-by: Kristina Martsenko <[email protected]>
---
 arch/arm64/include/asm/pointer_auth.h |  7 +------
 arch/arm64/include/asm/ptrauth-asm.h  | 26 ++++++++++++++++++++++++++
 arch/arm64/kernel/asm-offsets.c       |  7 +++++++
 arch/arm64/kernel/entry.S             |  9 +++++++--
 arch/arm64/kernel/process.c           |  1 -
 5 files changed, 41 insertions(+), 9 deletions(-)
 create mode 100644 arch/arm64/include/asm/ptrauth-asm.h

diff --git a/arch/arm64/include/asm/pointer_auth.h 
b/arch/arm64/include/asm/pointer_auth.h
index cedb03bd175b..5e40533f4ea2 100644
--- a/arch/arm64/include/asm/pointer_auth.h
+++ b/arch/arm64/include/asm/pointer_auth.h
@@ -64,16 +64,11 @@ static inline unsigned long ptrauth_strip_insn_pac(unsigned 
long ptr)
 }
 
 #define ptrauth_task_init_user(tsk)    \
-       ptrauth_keys_init(&(tsk)->thread_info.keys_user); \
-       ptrauth_keys_switch(&(tsk)->thread_info.keys_user)
-
-#define ptrauth_task_switch(tsk)       \
-       ptrauth_keys_switch(&(tsk)->thread_info.keys_user)
+       ptrauth_keys_init(&(tsk)->thread_info.keys_user)
 
 #else /* CONFIG_ARM64_PTR_AUTH */
 #define ptrauth_strip_insn_pac(lr)     (lr)
 #define ptrauth_task_init_user(tsk)
-#define ptrauth_task_switch(tsk)
 #endif /* CONFIG_ARM64_PTR_AUTH */
 
 #endif /* __ASM_POINTER_AUTH_H */
diff --git a/arch/arm64/include/asm/ptrauth-asm.h 
b/arch/arm64/include/asm/ptrauth-asm.h
new file mode 100644
index 000000000000..f50bdfc4046c
--- /dev/null
+++ b/arch/arm64/include/asm/ptrauth-asm.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_PTRAUTH_ASM_H
+#define __ASM_PTRAUTH_ASM_H
+
+#include <asm/asm-offsets.h>
+#include <asm/sysreg.h>
+
+#ifdef CONFIG_ARM64_PTR_AUTH
+
+       .macro ptrauth_keys_install_user tsk, tmp
+alternative_if ARM64_HAS_ADDRESS_AUTH
+       ldr     \tmp, [\tsk, #(TSK_TI_KEYS_USER + PTRAUTH_KEY_APIALO)]
+       msr_s   SYS_APIAKEYLO_EL1, \tmp
+       ldr     \tmp, [\tsk, #(TSK_TI_KEYS_USER + PTRAUTH_KEY_APIAHI)]
+       msr_s   SYS_APIAKEYHI_EL1, \tmp
+alternative_else_nop_endif
+       .endm
+
+#else /* CONFIG_ARM64_PTR_AUTH */
+
+       .macro ptrauth_keys_install_user tsk, tmp
+       .endm
+
+#endif /* CONFIG_ARM64_PTR_AUTH */
+
+#endif /* __ASM_PTRAUTH_ASM_H */
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 323aeb5f2fe6..b6be0dd037fd 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -45,6 +45,9 @@ int main(void)
 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
   DEFINE(TSK_TI_TTBR0,         offsetof(struct task_struct, 
thread_info.ttbr0));
 #endif
+#ifdef CONFIG_ARM64_PTR_AUTH
+  DEFINE(TSK_TI_KEYS_USER,     offsetof(struct task_struct, 
thread_info.keys_user));
+#endif
   DEFINE(TSK_STACK,            offsetof(struct task_struct, stack));
   BLANK();
   DEFINE(THREAD_CPU_CONTEXT,   offsetof(struct task_struct, 
thread.cpu_context));
@@ -169,5 +172,9 @@ int main(void)
   DEFINE(SDEI_EVENT_INTREGS,   offsetof(struct sdei_registered_event, 
interrupted_regs));
   DEFINE(SDEI_EVENT_PRIORITY,  offsetof(struct sdei_registered_event, 
priority));
 #endif
+#ifdef CONFIG_ARM64_PTR_AUTH
+  DEFINE(PTRAUTH_KEY_APIALO,   offsetof(struct ptrauth_keys, apia.lo));
+  DEFINE(PTRAUTH_KEY_APIAHI,   offsetof(struct ptrauth_keys, apia.hi));
+#endif
   return 0;
 }
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 09dbea221a27..1e925f6d2978 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -23,8 +23,9 @@
 #include <linux/linkage.h>
 
 #include <asm/alternative.h>
-#include <asm/assembler.h>
 #include <asm/asm-offsets.h>
+#include <asm/asm-uaccess.h>
+#include <asm/assembler.h>
 #include <asm/cpufeature.h>
 #include <asm/errno.h>
 #include <asm/esr.h>
@@ -33,8 +34,8 @@
 #include <asm/mmu.h>
 #include <asm/processor.h>
 #include <asm/ptrace.h>
+#include <asm/ptrauth-asm.h>
 #include <asm/thread_info.h>
-#include <asm/asm-uaccess.h>
 #include <asm/unistd.h>
 
 /*
@@ -325,6 +326,10 @@ alternative_else_nop_endif
        apply_ssbd 0, x0, x1
        .endif
 
+       .if     \el == 0
+       ptrauth_keys_install_user tsk, x0
+       .endif
+
        msr     elr_el1, x21                    // set up the return data
        msr     spsr_el1, x22
        ldp     x0, x1, [sp, #16 * 0]
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index fae52be66c92..857ae05cd04c 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -426,7 +426,6 @@ __notrace_funcgraph struct task_struct *__switch_to(struct 
task_struct *prev,
        contextidr_thread_switch(next);
        entry_task_switch(next);
        uao_thread_switch(next);
-       ptrauth_task_switch(next);
 
        /*
         * Complete any pending TLB or cache maintenance on this CPU in case
-- 
2.11.0

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