]> Git Repo - linux.git/commitdiff
arm64: simplify ptrauth initialization
authorMark Rutland <[email protected]>
Thu, 23 Apr 2020 10:16:06 +0000 (11:16 +0100)
committerWill Deacon <[email protected]>
Tue, 28 Apr 2020 10:23:21 +0000 (11:23 +0100)
Currently __cpu_setup conditionally initializes the address
authentication keys and enables them in SCTLR_EL1, doing so differently
for the primary CPU and secondary CPUs, and skipping this work for CPUs
returning from an idle state. For the latter case, cpu_do_resume
restores the keys and SCTLR_EL1 value after the MMU has been enabled.

This flow is rather difficult to follow, so instead let's move the
primary and secondary CPU initialization into their respective boot
paths. By following the example of cpu_do_resume and doing so once the
MMU is enabled, we can always initialize the keys from the values in
thread_struct, and avoid the machinery necessary to pass the keys in
secondary_data or open-coding initialization for the boot CPU.

This means we perform an additional RMW of SCTLR_EL1, but we already do
this in the cpu_do_resume path, and for other features in cpufeature.c,
so this isn't a major concern in a bringup path. Note that even while
the enable bits are clear, the key registers are accessible.

As this now renders the argument to __cpu_setup redundant, let's also
remove that entirely. Future extensions can follow a similar approach to
initialize values that differ for primary/secondary CPUs.

Signed-off-by: Mark Rutland <[email protected]>
Tested-by: Amit Daniel Kachhap <[email protected]>
Reviewed-by: Amit Daniel Kachhap <[email protected]>
Cc: Amit Daniel Kachhap <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: James Morse <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Cc: Will Deacon <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>
arch/arm64/include/asm/asm_pointer_auth.h
arch/arm64/include/asm/smp.h
arch/arm64/kernel/asm-offsets.c
arch/arm64/kernel/head.S
arch/arm64/kernel/sleep.S
arch/arm64/kernel/smp.c
arch/arm64/mm/proc.S

index c85540a911d3c2b28bb8fbd348f0d1ee87bc9187..52dead2a8640d2ef4acf30a0059e2d2c3413e906 100644 (file)
@@ -60,6 +60,28 @@ alternative_if ARM64_HAS_ADDRESS_AUTH
 alternative_else_nop_endif
        .endm
 
+       .macro __ptrauth_keys_init_cpu tsk, tmp1, tmp2, tmp3
+       mrs     \tmp1, id_aa64isar1_el1
+       ubfx    \tmp1, \tmp1, #ID_AA64ISAR1_APA_SHIFT, #8
+       cbz     \tmp1, .Lno_addr_auth\@
+       mov_q   \tmp1, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \
+                       SCTLR_ELx_ENDA | SCTLR_ELx_ENDB)
+       mrs     \tmp2, sctlr_el1
+       orr     \tmp2, \tmp2, \tmp1
+       msr     sctlr_el1, \tmp2
+       __ptrauth_keys_install_kernel_nosync \tsk, \tmp1, \tmp2, \tmp3
+       isb
+.Lno_addr_auth\@:
+       .endm
+
+       .macro ptrauth_keys_init_cpu tsk, tmp1, tmp2, tmp3
+alternative_if_not ARM64_HAS_ADDRESS_AUTH
+       b       .Lno_addr_auth\@
+alternative_else_nop_endif
+       __ptrauth_keys_init_cpu \tsk, \tmp1, \tmp2, \tmp3
+.Lno_addr_auth\@:
+       .endm
+
 #else /* CONFIG_ARM64_PTR_AUTH */
 
        .macro ptrauth_keys_install_user tsk, tmp1, tmp2, tmp3
index 40d5ba029615f63ff53a65ab9e1fbe2425a5d359..ea268d88b6f7e6e5318c8c9671dedb740b0d6dc1 100644 (file)
 #define CPU_STUCK_REASON_52_BIT_VA     (UL(1) << CPU_STUCK_REASON_SHIFT)
 #define CPU_STUCK_REASON_NO_GRAN       (UL(2) << CPU_STUCK_REASON_SHIFT)
 
-/* Possible options for __cpu_setup */
-/* Option to setup primary cpu */
-#define ARM64_CPU_BOOT_PRIMARY         (1)
-/* Option to setup secondary cpus */
-#define ARM64_CPU_BOOT_SECONDARY       (2)
-/* Option to setup cpus for different cpu run time services */
-#define ARM64_CPU_RUNTIME              (3)
-
 #ifndef __ASSEMBLY__
 
 #include <asm/percpu.h>
@@ -96,9 +88,6 @@ asmlinkage void secondary_start_kernel(void);
 struct secondary_data {
        void *stack;
        struct task_struct *task;
-#ifdef CONFIG_ARM64_PTR_AUTH
-       struct ptrauth_keys_kernel ptrauth_key;
-#endif
        long status;
 };
 
index 9981a0a5a87f13b86067520f8ae1cf23a2a6fd9a..890ddd67b8bff8a1bbcbb6b23aa7050cdefd4bc2 100644 (file)
@@ -92,9 +92,6 @@ int main(void)
   BLANK();
   DEFINE(CPU_BOOT_STACK,       offsetof(struct secondary_data, stack));
   DEFINE(CPU_BOOT_TASK,                offsetof(struct secondary_data, task));
-#ifdef CONFIG_ARM64_PTR_AUTH
-  DEFINE(CPU_BOOT_PTRAUTH_KEY, offsetof(struct secondary_data, ptrauth_key));
-#endif
   BLANK();
 #ifdef CONFIG_KVM_ARM_HOST
   DEFINE(VCPU_CONTEXT,         offsetof(struct kvm_vcpu, arch.ctxt));
index 57a91032b4c21ca2dc74447c10093f0d4dd0cec7..dc2b441d4ed804520a8de9813973af694a8401d4 100644 (file)
@@ -13,6 +13,7 @@
 #include <linux/init.h>
 #include <linux/irqchip/arm-gic-v3.h>
 
+#include <asm/asm_pointer_auth.h>
 #include <asm/assembler.h>
 #include <asm/boot.h>
 #include <asm/ptrace.h>
@@ -118,7 +119,6 @@ SYM_CODE_START(stext)
         * On return, the CPU will be ready for the MMU to be turned on and
         * the TCR will have been set.
         */
-       mov     x0, #ARM64_CPU_BOOT_PRIMARY
        bl      __cpu_setup                     // initialise processor
        b       __primary_switch
 SYM_CODE_END(stext)
@@ -417,6 +417,10 @@ 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
@@ -717,7 +721,6 @@ SYM_FUNC_START_LOCAL(secondary_startup)
         * Common entry point for secondary CPUs.
         */
        bl      __cpu_secondary_check52bitva
-       mov     x0, #ARM64_CPU_BOOT_SECONDARY
        bl      __cpu_setup                     // initialise processor
        adrp    x1, swapper_pg_dir
        bl      __enable_mmu
@@ -739,6 +742,11 @@ SYM_FUNC_START_LOCAL(__secondary_switched)
        msr     sp_el0, x2
        mov     x29, #0
        mov     x30, #0
+
+#ifdef CONFIG_ARM64_PTR_AUTH
+       ptrauth_keys_init_cpu x2, x3, x4, x5
+#endif
+
        b       secondary_start_kernel
 SYM_FUNC_END(__secondary_switched)
 
index 7b2f2e650c44d01aacbafa4562a9d986f5316f4e..56b1fe9bfaa0b96b53aadbb4b85193c5d92c3baf 100644 (file)
@@ -100,7 +100,6 @@ ENDPROC(__cpu_suspend_enter)
        .pushsection ".idmap.text", "awx"
 ENTRY(cpu_resume)
        bl      el2_setup               // if in EL2 drop to EL1 cleanly
-       mov     x0, #ARM64_CPU_RUNTIME
        bl      __cpu_setup
        /* enable the MMU early - so we can access sleep_save_stash by va */
        adrp    x1, swapper_pg_dir
index 061f60fe452f773e233c0bffc68b0c614db905a4..d6d337d036f0cfdbe9f5f7f3ad584900eae56a98 100644 (file)
@@ -114,10 +114,6 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
         */
        secondary_data.task = idle;
        secondary_data.stack = task_stack_page(idle) + THREAD_SIZE;
-#if defined(CONFIG_ARM64_PTR_AUTH)
-       secondary_data.ptrauth_key.apia.lo = idle->thread.keys_kernel.apia.lo;
-       secondary_data.ptrauth_key.apia.hi = idle->thread.keys_kernel.apia.hi;
-#endif
        update_cpu_boot_status(CPU_MMU_OFF);
        __flush_dcache_area(&secondary_data, sizeof(secondary_data));
 
@@ -140,10 +136,6 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
        pr_crit("CPU%u: failed to come online\n", cpu);
        secondary_data.task = NULL;
        secondary_data.stack = NULL;
-#if defined(CONFIG_ARM64_PTR_AUTH)
-       secondary_data.ptrauth_key.apia.lo = 0;
-       secondary_data.ptrauth_key.apia.hi = 0;
-#endif
        __flush_dcache_area(&secondary_data, sizeof(secondary_data));
        status = READ_ONCE(secondary_data.status);
        if (status == CPU_MMU_OFF)
index 0401342741e60a67658e91b4f119412141fa6100..7d3bf1afba0ced636a4c3a483e6bef951c204305 100644 (file)
@@ -386,8 +386,6 @@ SYM_FUNC_END(idmap_kpti_install_ng_mappings)
  *
  *     Initialise the processor for turning the MMU on.
  *
- * Input:
- *     x0 with a flag ARM64_CPU_BOOT_PRIMARY/ARM64_CPU_BOOT_SECONDARY/ARM64_CPU_RUNTIME.
  * Output:
  *     Return in x0 the value of the SCTLR_EL1 register.
  */
@@ -446,51 +444,9 @@ SYM_FUNC_START(__cpu_setup)
 1:
 #endif /* CONFIG_ARM64_HW_AFDBM */
        msr     tcr_el1, x10
-       mov     x1, x0
        /*
         * Prepare SCTLR
         */
        mov_q   x0, SCTLR_EL1_SET
-
-#ifdef CONFIG_ARM64_PTR_AUTH
-       /* No ptrauth setup for run time cpus */
-       cmp     x1, #ARM64_CPU_RUNTIME
-       b.eq    3f
-
-       /* Check if the CPU supports ptrauth */
-       mrs     x2, id_aa64isar1_el1
-       ubfx    x2, x2, #ID_AA64ISAR1_APA_SHIFT, #8
-       cbz     x2, 3f
-
-       /*
-        * The primary cpu keys are reset here and can be
-        * re-initialised with some proper values later.
-        */
-       msr_s   SYS_APIAKEYLO_EL1, xzr
-       msr_s   SYS_APIAKEYHI_EL1, xzr
-
-       /* Just enable ptrauth for primary cpu */
-       cmp     x1, #ARM64_CPU_BOOT_PRIMARY
-       b.eq    2f
-
-       /* if !system_supports_address_auth() then skip enable */
-alternative_if_not ARM64_HAS_ADDRESS_AUTH
-       b       3f
-alternative_else_nop_endif
-
-       /* Install ptrauth key for secondary cpus */
-       adr_l   x2, secondary_data
-       ldr     x3, [x2, #CPU_BOOT_TASK]        // get secondary_data.task
-       cbz     x3, 2f                          // check for slow booting cpus
-       ldp     x3, x4, [x2, #CPU_BOOT_PTRAUTH_KEY]
-       msr_s   SYS_APIAKEYLO_EL1, x3
-       msr_s   SYS_APIAKEYHI_EL1, x4
-
-2:     /* Enable ptrauth instructions */
-       ldr     x2, =SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \
-                    SCTLR_ELx_ENDA | SCTLR_ELx_ENDB
-       orr     x0, x0, x2
-3:
-#endif
        ret                                     // return to head.S
 SYM_FUNC_END(__cpu_setup)
This page took 0.077398 seconds and 4 git commands to generate.