From cabe1c81ea5be983425d117912d7883e252a3b09 Mon Sep 17 00:00:00 2001 From: James Morse Date: Wed, 27 Apr 2016 17:47:07 +0100 Subject: [PATCH] arm64: Change cpu_resume() to enable mmu early then access sleep_sp by va By enabling the MMU early in cpu_resume(), the sleep_save_sp and stack can be accessed by VA, which avoids the need to convert-addresses and clean to PoC on the suspend path. MMU setup is shared with the boot path, meaning the swapper_pg_dir is restored directly: ttbr1_el1 is no longer saved/restored. struct sleep_save_sp is removed, replacing it with a single array of pointers. cpu_do_{suspend,resume} could be further reduced to not restore: cpacr_el1, mdscr_el1, tcr_el1, vbar_el1 and sctlr_el1, all of which are set by __cpu_setup(). However these values all contain res0 bits that may be used to enable future features. Signed-off-by: James Morse Reviewed-by: Lorenzo Pieralisi Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon --- arch/arm64/include/asm/suspend.h | 9 ++--- arch/arm64/kernel/asm-offsets.c | 3 -- arch/arm64/kernel/head.S | 2 +- arch/arm64/kernel/setup.c | 1 - arch/arm64/kernel/sleep.S | 66 +++++++++++++------------------- arch/arm64/kernel/suspend.c | 38 +++--------------- arch/arm64/mm/proc.S | 53 ++++++++++--------------- 7 files changed, 57 insertions(+), 115 deletions(-) diff --git a/arch/arm64/include/asm/suspend.h b/arch/arm64/include/asm/suspend.h index 365d8cdd0073..29d3c71433e1 100644 --- a/arch/arm64/include/asm/suspend.h +++ b/arch/arm64/include/asm/suspend.h @@ -1,7 +1,7 @@ #ifndef __ASM_SUSPEND_H #define __ASM_SUSPEND_H -#define NR_CTX_REGS 11 +#define NR_CTX_REGS 10 #define NR_CALLEE_SAVED_REGS 12 /* @@ -17,11 +17,6 @@ struct cpu_suspend_ctx { u64 sp; } __aligned(16); -struct sleep_save_sp { - phys_addr_t *save_ptr_stash; - phys_addr_t save_ptr_stash_phys; -}; - /* * Memory to save the cpu state is allocated on the stack by * __cpu_suspend_enter()'s caller, and populated by __cpu_suspend_enter(). @@ -39,6 +34,8 @@ struct sleep_stack_data { unsigned long callee_saved_regs[NR_CALLEE_SAVED_REGS]; }; +extern unsigned long *sleep_save_stash; + extern int cpu_suspend(unsigned long arg, int (*fn)(unsigned long)); extern void cpu_resume(void); int __cpu_suspend_enter(struct sleep_stack_data *state); diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index 0902acb7afe5..ac742ef0fde0 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -119,9 +119,6 @@ int main(void) DEFINE(CPU_CTX_SP, offsetof(struct cpu_suspend_ctx, sp)); DEFINE(MPIDR_HASH_MASK, offsetof(struct mpidr_hash, mask)); DEFINE(MPIDR_HASH_SHIFTS, offsetof(struct mpidr_hash, shift_aff)); - DEFINE(SLEEP_SAVE_SP_SZ, sizeof(struct sleep_save_sp)); - DEFINE(SLEEP_SAVE_SP_PHYS, offsetof(struct sleep_save_sp, save_ptr_stash_phys)); - DEFINE(SLEEP_SAVE_SP_VIRT, offsetof(struct sleep_save_sp, save_ptr_stash)); DEFINE(SLEEP_STACK_DATA_SYSTEM_REGS, offsetof(struct sleep_stack_data, system_regs)); DEFINE(SLEEP_STACK_DATA_CALLEE_REGS, offsetof(struct sleep_stack_data, callee_saved_regs)); #endif diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 00a32101ab51..0674384cfc74 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -716,7 +716,7 @@ ENTRY(__early_cpu_boot_status) * If it isn't, park the CPU */ .section ".idmap.text", "ax" -__enable_mmu: +ENTRY(__enable_mmu) mrs x22, sctlr_el1 // preserve old SCTLR_EL1 value mrs x1, ID_AA64MMFR0_EL1 ubfx x2, x1, #ID_AA64MMFR0_TGRAN_SHIFT, 4 diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 65f515949baa..3279defabaa2 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -176,7 +176,6 @@ static void __init smp_build_mpidr_hash(void) */ if (mpidr_hash_size() > 4 * num_possible_cpus()) pr_warn("Large number of MPIDR hash buckets detected\n"); - __flush_dcache_area(&mpidr_hash, sizeof(struct mpidr_hash)); } static void __init setup_machine_fdt(phys_addr_t dt_phys) diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S index b7c4b682bfc8..9a3aec97ac09 100644 --- a/arch/arm64/kernel/sleep.S +++ b/arch/arm64/kernel/sleep.S @@ -73,8 +73,8 @@ ENTRY(__cpu_suspend_enter) str x2, [x0, #SLEEP_STACK_DATA_SYSTEM_REGS + CPU_CTX_SP] /* find the mpidr_hash */ - ldr x1, =sleep_save_sp - ldr x1, [x1, #SLEEP_SAVE_SP_VIRT] + ldr x1, =sleep_save_stash + ldr x1, [x1] mrs x7, mpidr_el1 ldr x9, =mpidr_hash ldr x10, [x9, #MPIDR_HASH_MASK] @@ -87,44 +87,27 @@ ENTRY(__cpu_suspend_enter) compute_mpidr_hash x8, x3, x4, x5, x6, x7, x10 add x1, x1, x8, lsl #3 + str x0, [x1] + add x0, x0, #SLEEP_STACK_DATA_SYSTEM_REGS stp x29, lr, [sp, #-16]! - bl __cpu_suspend_save + bl cpu_do_suspend ldp x29, lr, [sp], #16 mov x0, #1 ret ENDPROC(__cpu_suspend_enter) .ltorg -/* - * x0 must contain the sctlr value retrieved from restored context - */ - .pushsection ".idmap.text", "ax" -ENTRY(cpu_resume_mmu) - ldr x3, =cpu_resume_after_mmu - msr sctlr_el1, x0 // restore sctlr_el1 - isb - /* - * Invalidate the local I-cache so that any instructions fetched - * speculatively from the PoC are discarded, since they may have - * been dynamically patched at the PoU. - */ - ic iallu - dsb nsh - isb - br x3 // global jump to virtual address -ENDPROC(cpu_resume_mmu) - .popsection -cpu_resume_after_mmu: -#ifdef CONFIG_KASAN - mov x0, sp - bl kasan_unpoison_remaining_stack -#endif - mov x0, #0 // return zero on success - ret -ENDPROC(cpu_resume_after_mmu) - ENTRY(cpu_resume) bl el2_setup // if in EL2 drop to EL1 cleanly + /* enable the MMU early - so we can access sleep_save_stash by va */ + adr_l lr, __enable_mmu /* __cpu_setup will return here */ + ldr x27, =_cpu_resume /* __enable_mmu will branch here */ + adrp x25, idmap_pg_dir + adrp x26, swapper_pg_dir + b __cpu_setup +ENDPROC(cpu_resume) + +ENTRY(_cpu_resume) mrs x1, mpidr_el1 adrp x8, mpidr_hash add x8, x8, #:lo12:mpidr_hash // x8 = struct mpidr_hash phys address @@ -134,29 +117,32 @@ ENTRY(cpu_resume) ldp w5, w6, [x8, #(MPIDR_HASH_SHIFTS + 8)] compute_mpidr_hash x7, x3, x4, x5, x6, x1, x2 /* x7 contains hash index, let's use it to grab context pointer */ - ldr_l x0, sleep_save_sp + SLEEP_SAVE_SP_PHYS + ldr_l x0, sleep_save_stash ldr x0, [x0, x7, lsl #3] add x29, x0, #SLEEP_STACK_DATA_CALLEE_REGS add x0, x0, #SLEEP_STACK_DATA_SYSTEM_REGS /* load sp from context */ ldr x2, [x0, #CPU_CTX_SP] - /* load physical address of identity map page table in x1 */ - adrp x1, idmap_pg_dir mov sp, x2 /* save thread_info */ and x2, x2, #~(THREAD_SIZE - 1) msr sp_el0, x2 /* - * cpu_do_resume expects x0 to contain context physical address - * pointer and x1 to contain physical address of 1:1 page tables + * cpu_do_resume expects x0 to contain context address pointer */ - bl cpu_do_resume // PC relative jump, MMU off - /* Can't access these by physical address once the MMU is on */ + bl cpu_do_resume + +#ifdef CONFIG_KASAN + mov x0, sp + bl kasan_unpoison_remaining_stack +#endif + ldp x19, x20, [x29, #16] ldp x21, x22, [x29, #32] ldp x23, x24, [x29, #48] ldp x25, x26, [x29, #64] ldp x27, x28, [x29, #80] ldp x29, lr, [x29] - b cpu_resume_mmu // Resume MMU, never returns -ENDPROC(cpu_resume) + mov x0, #0 + ret +ENDPROC(_cpu_resume) diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c index 0d52ec972a38..b616e365cee3 100644 --- a/arch/arm64/kernel/suspend.c +++ b/arch/arm64/kernel/suspend.c @@ -10,30 +10,11 @@ #include #include - /* - * This is called by __cpu_suspend_enter() to save the state, and do whatever - * flushing is required to ensure that when the CPU goes to sleep we have - * the necessary data available when the caches are not searched. - * - * ptr: sleep_stack_data containing cpu state virtual address. - * save_ptr: address of the location where the context physical address - * must be saved + * This is allocated by cpu_suspend_init(), and used to store a pointer to + * the 'struct sleep_stack_data' the contains a particular CPUs state. */ -void notrace __cpu_suspend_save(struct sleep_stack_data *ptr, - phys_addr_t *save_ptr) -{ - *save_ptr = virt_to_phys(ptr); - - cpu_do_suspend(&ptr->system_regs); - /* - * Only flush the context that must be retrieved with the MMU - * off. VA primitives ensure the flush is applied to all - * cache levels so context is pushed to DRAM. - */ - __flush_dcache_area(ptr, sizeof(*ptr)); - __flush_dcache_area(save_ptr, sizeof(*save_ptr)); -} +unsigned long *sleep_save_stash; /* * This hook is provided so that cpu_suspend code can restore HW @@ -131,22 +112,15 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long)) return ret; } -struct sleep_save_sp sleep_save_sp; - static int __init cpu_suspend_init(void) { - void *ctx_ptr; - /* ctx_ptr is an array of physical addresses */ - ctx_ptr = kcalloc(mpidr_hash_size(), sizeof(phys_addr_t), GFP_KERNEL); + sleep_save_stash = kcalloc(mpidr_hash_size(), sizeof(*sleep_save_stash), + GFP_KERNEL); - if (WARN_ON(!ctx_ptr)) + if (WARN_ON(!sleep_save_stash)) return -ENOMEM; - sleep_save_sp.save_ptr_stash = ctx_ptr; - sleep_save_sp.save_ptr_stash_phys = virt_to_phys(ctx_ptr); - __flush_dcache_area(&sleep_save_sp, sizeof(struct sleep_save_sp)); - return 0; } early_initcall(cpu_suspend_init); diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 9f6deacf41d2..c4317879b938 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -24,6 +24,7 @@ #include #include #include +#include #include #include @@ -63,62 +64,50 @@ ENTRY(cpu_do_suspend) mrs x2, tpidr_el0 mrs x3, tpidrro_el0 mrs x4, contextidr_el1 - mrs x5, mair_el1 - mrs x6, cpacr_el1 - mrs x7, ttbr1_el1 - mrs x8, tcr_el1 - mrs x9, vbar_el1 - mrs x10, mdscr_el1 - mrs x11, oslsr_el1 - mrs x12, sctlr_el1 + mrs x5, cpacr_el1 + mrs x6, tcr_el1 + mrs x7, vbar_el1 + mrs x8, mdscr_el1 + mrs x9, oslsr_el1 + mrs x10, sctlr_el1 stp x2, x3, [x0] - stp x4, x5, [x0, #16] - stp x6, x7, [x0, #32] - stp x8, x9, [x0, #48] - stp x10, x11, [x0, #64] - str x12, [x0, #80] + stp x4, xzr, [x0, #16] + stp x5, x6, [x0, #32] + stp x7, x8, [x0, #48] + stp x9, x10, [x0, #64] ret ENDPROC(cpu_do_suspend) /** * cpu_do_resume - restore CPU register context * - * x0: Physical address of context pointer - * x1: ttbr0_el1 to be restored - * - * Returns: - * sctlr_el1 value in x0 + * x0: Address of context pointer */ ENTRY(cpu_do_resume) - /* - * Invalidate local tlb entries before turning on MMU - */ - tlbi vmalle1 ldp x2, x3, [x0] ldp x4, x5, [x0, #16] - ldp x6, x7, [x0, #32] - ldp x8, x9, [x0, #48] - ldp x10, x11, [x0, #64] - ldr x12, [x0, #80] + ldp x6, x8, [x0, #32] + ldp x9, x10, [x0, #48] + ldp x11, x12, [x0, #64] msr tpidr_el0, x2 msr tpidrro_el0, x3 msr contextidr_el1, x4 - msr mair_el1, x5 msr cpacr_el1, x6 - msr ttbr0_el1, x1 - msr ttbr1_el1, x7 - tcr_set_idmap_t0sz x8, x7 + + /* Don't change t0sz here, mask those bits when restoring */ + mrs x5, tcr_el1 + bfi x8, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH + msr tcr_el1, x8 msr vbar_el1, x9 msr mdscr_el1, x10 + msr sctlr_el1, x12 /* * Restore oslsr_el1 by writing oslar_el1 */ ubfx x11, x11, #1, #1 msr oslar_el1, x11 reset_pmuserenr_el0 x0 // Disable PMU access from EL0 - mov x0, x12 - dsb nsh // Make sure local tlb invalidation completed isb ret ENDPROC(cpu_do_resume)