* [PATCH 0/2] arm64: pointer authentication initialization cleanup
@ 2020-04-23 10:16 Mark Rutland
2020-04-23 10:16 ` [PATCH 1/2] arm64: remove ptrauth_keys_install_kernel sync arg Mark Rutland
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Mark Rutland @ 2020-04-23 10:16 UTC (permalink / raw)
To: linux-arm-kernel
Cc: mark.rutland, suzuki.poulose, catalin.marinas, james.morse,
amit.kachhap, will
These patches refactor the pointer authentication initialization code to make
it easier to reason about and to reduce duplication of code.
The big wins are:
* Moving the initialization after the MMU has been enabled. This means we can
initialize the keys using the same helpers as context switch, and don't need
to temporarily duplicate them in secondary_data.
* Moving primary/secondary conditional initialization into the respective
primary/secondary boot paths. This minimizes potentially-confusing control
flow and still allows for code sharing via helper macros.
I've given this a spin on a foundation model, with userspace and kernel tests,
playing with CPU hotplug, etc.
Patches based on v5.7-rc2. These have no dependency on my fix queued in
for-next/core.
Thanks,
Mark.
Mark Rutland (2):
arm64: remove ptrauth_keys_install_kernel sync arg
arm64: simplify ptrauth initialization
arch/arm64/include/asm/asm_pointer_auth.h | 43 +++++++++++++++++++++++++----
arch/arm64/include/asm/smp.h | 11 --------
arch/arm64/kernel/asm-offsets.c | 3 --
arch/arm64/kernel/entry.S | 4 +--
arch/arm64/kernel/head.S | 12 ++++++--
arch/arm64/kernel/sleep.S | 1 -
arch/arm64/kernel/smp.c | 8 ------
arch/arm64/mm/proc.S | 46 +------------------------------
8 files changed, 51 insertions(+), 77 deletions(-)
--
2.11.0
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^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH 1/2] arm64: remove ptrauth_keys_install_kernel sync arg 2020-04-23 10:16 [PATCH 0/2] arm64: pointer authentication initialization cleanup Mark Rutland @ 2020-04-23 10:16 ` Mark Rutland 2020-04-23 10:16 ` [PATCH 2/2] arm64: simplify ptrauth initialization Mark Rutland 2020-04-28 10:43 ` [PATCH 0/2] arm64: pointer authentication initialization cleanup Will Deacon 2 siblings, 0 replies; 6+ messages in thread From: Mark Rutland @ 2020-04-23 10:16 UTC (permalink / raw) To: linux-arm-kernel Cc: mark.rutland, suzuki.poulose, catalin.marinas, james.morse, amit.kachhap, will The 'sync' argument to ptrauth_keys_install_kernel macro is somewhat opaque at callsites, so instead lets have regular and _nosync variants of the macro to make this a little more obvious. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Amit Daniel Kachhap <amit.kachhap@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/asm_pointer_auth.h | 21 ++++++++++++++++----- arch/arm64/kernel/entry.S | 4 ++-- arch/arm64/mm/proc.S | 2 +- 3 files changed, 19 insertions(+), 8 deletions(-) diff --git a/arch/arm64/include/asm/asm_pointer_auth.h b/arch/arm64/include/asm/asm_pointer_auth.h index ce2a8486992b..c85540a911d3 100644 --- a/arch/arm64/include/asm/asm_pointer_auth.h +++ b/arch/arm64/include/asm/asm_pointer_auth.h @@ -39,16 +39,24 @@ alternative_if ARM64_HAS_GENERIC_AUTH alternative_else_nop_endif .endm - .macro ptrauth_keys_install_kernel tsk, sync, tmp1, tmp2, tmp3 -alternative_if ARM64_HAS_ADDRESS_AUTH + .macro __ptrauth_keys_install_kernel_nosync tsk, tmp1, tmp2, tmp3 mov \tmp1, #THREAD_KEYS_KERNEL add \tmp1, \tsk, \tmp1 ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_KERNEL_KEY_APIA] msr_s SYS_APIAKEYLO_EL1, \tmp2 msr_s SYS_APIAKEYHI_EL1, \tmp3 - .if \sync == 1 + .endm + + .macro ptrauth_keys_install_kernel_nosync tsk, tmp1, tmp2, tmp3 +alternative_if ARM64_HAS_ADDRESS_AUTH + __ptrauth_keys_install_kernel_nosync \tsk, \tmp1, \tmp2, \tmp3 +alternative_else_nop_endif + .endm + + .macro ptrauth_keys_install_kernel tsk, tmp1, tmp2, tmp3 +alternative_if ARM64_HAS_ADDRESS_AUTH + __ptrauth_keys_install_kernel_nosync \tsk, \tmp1, \tmp2, \tmp3 isb - .endif alternative_else_nop_endif .endm @@ -57,7 +65,10 @@ alternative_else_nop_endif .macro ptrauth_keys_install_user tsk, tmp1, tmp2, tmp3 .endm - .macro ptrauth_keys_install_kernel tsk, sync, tmp1, tmp2, tmp3 + .macro ptrauth_keys_install_kernel_nosync tsk, tmp1, tmp2, tmp3 + .endm + + .macro ptrauth_keys_install_kernel tsk, tmp1, tmp2, tmp3 .endm #endif /* CONFIG_ARM64_PTR_AUTH */ diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index ddcde093c433..a9265fef914f 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -178,7 +178,7 @@ alternative_cb_end apply_ssbd 1, x22, x23 - ptrauth_keys_install_kernel tsk, 1, x20, x22, x23 + ptrauth_keys_install_kernel tsk, x20, x22, x23 .else add x21, sp, #S_FRAME_SIZE get_current_task tsk @@ -900,7 +900,7 @@ SYM_FUNC_START(cpu_switch_to) ldr lr, [x8] mov sp, x9 msr sp_el0, x1 - ptrauth_keys_install_kernel x1, 1, x8, x9, x10 + ptrauth_keys_install_kernel x1, x8, x9, x10 ret SYM_FUNC_END(cpu_switch_to) NOKPROBE(cpu_switch_to) diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 197a9ba2d5ea..0401342741e6 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -139,7 +139,7 @@ alternative_if ARM64_HAS_RAS_EXTN msr_s SYS_DISR_EL1, xzr alternative_else_nop_endif - ptrauth_keys_install_kernel x14, 0, x1, x2, x3 + ptrauth_keys_install_kernel_nosync x14, x1, x2, x3 isb ret SYM_FUNC_END(cpu_do_resume) -- 2.11.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/2] arm64: simplify ptrauth initialization 2020-04-23 10:16 [PATCH 0/2] arm64: pointer authentication initialization cleanup Mark Rutland 2020-04-23 10:16 ` [PATCH 1/2] arm64: remove ptrauth_keys_install_kernel sync arg Mark Rutland @ 2020-04-23 10:16 ` Mark Rutland 2020-04-23 14:35 ` Amit Kachhap 2020-04-28 10:43 ` [PATCH 0/2] arm64: pointer authentication initialization cleanup Will Deacon 2 siblings, 1 reply; 6+ messages in thread From: Mark Rutland @ 2020-04-23 10:16 UTC (permalink / raw) To: linux-arm-kernel Cc: mark.rutland, suzuki.poulose, catalin.marinas, james.morse, amit.kachhap, will 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 <mark.rutland@arm.com> Cc: Amit Daniel Kachhap <amit.kachhap@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/asm_pointer_auth.h | 22 ++++++++++++++++ arch/arm64/include/asm/smp.h | 11 -------- arch/arm64/kernel/asm-offsets.c | 3 --- arch/arm64/kernel/head.S | 12 +++++++-- arch/arm64/kernel/sleep.S | 1 - arch/arm64/kernel/smp.c | 8 ------ arch/arm64/mm/proc.S | 44 ------------------------------- 7 files changed, 32 insertions(+), 69 deletions(-) diff --git a/arch/arm64/include/asm/asm_pointer_auth.h b/arch/arm64/include/asm/asm_pointer_auth.h index c85540a911d3..52dead2a8640 100644 --- a/arch/arm64/include/asm/asm_pointer_auth.h +++ b/arch/arm64/include/asm/asm_pointer_auth.h @@ -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 diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h index 40d5ba029615..ea268d88b6f7 100644 --- a/arch/arm64/include/asm/smp.h +++ b/arch/arm64/include/asm/smp.h @@ -23,14 +23,6 @@ #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; }; diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index 9981a0a5a87f..890ddd67b8bf 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -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)); diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 57a91032b4c2..dc2b441d4ed8 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -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) diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S index 7b2f2e650c44..56b1fe9bfaa0 100644 --- a/arch/arm64/kernel/sleep.S +++ b/arch/arm64/kernel/sleep.S @@ -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 diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 061f60fe452f..d6d337d036f0 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -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) diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 0401342741e6..7d3bf1afba0c 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -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) -- 2.11.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 2/2] arm64: simplify ptrauth initialization 2020-04-23 10:16 ` [PATCH 2/2] arm64: simplify ptrauth initialization Mark Rutland @ 2020-04-23 14:35 ` Amit Kachhap 2020-04-23 16:06 ` Mark Rutland 0 siblings, 1 reply; 6+ messages in thread From: Amit Kachhap @ 2020-04-23 14:35 UTC (permalink / raw) To: Mark Rutland, linux-arm-kernel Cc: catalin.marinas, james.morse, will, suzuki.poulose Hi, On 4/23/20 3:46 PM, Mark Rutland wrote: > 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 <mark.rutland@arm.com> > Cc: Amit Daniel Kachhap <amit.kachhap@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: James Morse <james.morse@arm.com> > Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > Cc: Will Deacon <will@kernel.org> The code changes look good. I couldn't find any problem while testing it. Tested-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Reviewed-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Thanks, Amit > --- > arch/arm64/include/asm/asm_pointer_auth.h | 22 ++++++++++++++++ > arch/arm64/include/asm/smp.h | 11 -------- > arch/arm64/kernel/asm-offsets.c | 3 --- > arch/arm64/kernel/head.S | 12 +++++++-- > arch/arm64/kernel/sleep.S | 1 - > arch/arm64/kernel/smp.c | 8 ------ > arch/arm64/mm/proc.S | 44 ------------------------------- > 7 files changed, 32 insertions(+), 69 deletions(-) > > diff --git a/arch/arm64/include/asm/asm_pointer_auth.h b/arch/arm64/include/asm/asm_pointer_auth.h > index c85540a911d3..52dead2a8640 100644 > --- a/arch/arm64/include/asm/asm_pointer_auth.h > +++ b/arch/arm64/include/asm/asm_pointer_auth.h > @@ -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 > diff --git a/arch/arm64/include/asm/smp.h b/arch/arm64/include/asm/smp.h > index 40d5ba029615..ea268d88b6f7 100644 > --- a/arch/arm64/include/asm/smp.h > +++ b/arch/arm64/include/asm/smp.h > @@ -23,14 +23,6 @@ > #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; > }; > > diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c > index 9981a0a5a87f..890ddd67b8bf 100644 > --- a/arch/arm64/kernel/asm-offsets.c > +++ b/arch/arm64/kernel/asm-offsets.c > @@ -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)); > diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S > index 57a91032b4c2..dc2b441d4ed8 100644 > --- a/arch/arm64/kernel/head.S > +++ b/arch/arm64/kernel/head.S > @@ -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) > > diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S > index 7b2f2e650c44..56b1fe9bfaa0 100644 > --- a/arch/arm64/kernel/sleep.S > +++ b/arch/arm64/kernel/sleep.S > @@ -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 > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > index 061f60fe452f..d6d337d036f0 100644 > --- a/arch/arm64/kernel/smp.c > +++ b/arch/arm64/kernel/smp.c > @@ -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) > diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S > index 0401342741e6..7d3bf1afba0c 100644 > --- a/arch/arm64/mm/proc.S > +++ b/arch/arm64/mm/proc.S > @@ -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) > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 2/2] arm64: simplify ptrauth initialization 2020-04-23 14:35 ` Amit Kachhap @ 2020-04-23 16:06 ` Mark Rutland 0 siblings, 0 replies; 6+ messages in thread From: Mark Rutland @ 2020-04-23 16:06 UTC (permalink / raw) To: Amit Kachhap Cc: catalin.marinas, will, james.morse, linux-arm-kernel, suzuki.poulose On Thu, Apr 23, 2020 at 08:05:42PM +0530, Amit Kachhap wrote: > Hi, > > On 4/23/20 3:46 PM, Mark Rutland wrote: > > 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 <mark.rutland@arm.com> > > Cc: Amit Daniel Kachhap <amit.kachhap@arm.com> > > Cc: Catalin Marinas <catalin.marinas@arm.com> > > Cc: James Morse <james.morse@arm.com> > > Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > > Cc: Will Deacon <will@kernel.org> > > The code changes look good. I couldn't find any problem while testing it. > > Tested-by: Amit Daniel Kachhap <amit.kachhap@arm.com> > Reviewed-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Thanks; that's much appreciated! Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 0/2] arm64: pointer authentication initialization cleanup 2020-04-23 10:16 [PATCH 0/2] arm64: pointer authentication initialization cleanup Mark Rutland 2020-04-23 10:16 ` [PATCH 1/2] arm64: remove ptrauth_keys_install_kernel sync arg Mark Rutland 2020-04-23 10:16 ` [PATCH 2/2] arm64: simplify ptrauth initialization Mark Rutland @ 2020-04-28 10:43 ` Will Deacon 2 siblings, 0 replies; 6+ messages in thread From: Will Deacon @ 2020-04-28 10:43 UTC (permalink / raw) To: linux-arm-kernel, Mark Rutland Cc: amit.kachhap, catalin.marinas, Will Deacon, james.morse, suzuki.poulose On Thu, 23 Apr 2020 11:16:04 +0100, Mark Rutland wrote: > These patches refactor the pointer authentication initialization code to make > it easier to reason about and to reduce duplication of code. > > The big wins are: > > * Moving the initialization after the MMU has been enabled. This means we can > initialize the keys using the same helpers as context switch, and don't need > to temporarily duplicate them in secondary_data. > > [...] Applied to arm64 (for-next/ptr-auth), thanks! [1/2] arm64: remove ptrauth_keys_install_kernel sync arg https://git.kernel.org/arm64/c/d0055da5266a [2/2] arm64: simplify ptrauth initialization https://git.kernel.org/arm64/c/62a679cb2825 Cheers, -- Will https://fixes.arm64.dev https://next.arm64.dev _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-04-28 10:43 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2020-04-23 10:16 [PATCH 0/2] arm64: pointer authentication initialization cleanup Mark Rutland 2020-04-23 10:16 ` [PATCH 1/2] arm64: remove ptrauth_keys_install_kernel sync arg Mark Rutland 2020-04-23 10:16 ` [PATCH 2/2] arm64: simplify ptrauth initialization Mark Rutland 2020-04-23 14:35 ` Amit Kachhap 2020-04-23 16:06 ` Mark Rutland 2020-04-28 10:43 ` [PATCH 0/2] arm64: pointer authentication initialization cleanup Will Deacon
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