From 3c5e9f238bc475b0712419eaebc643c07c73cb94 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 31 Aug 2016 12:05:13 +0100 Subject: [PATCH] arm64: head.S: move KASLR processing out of __enable_mmu() The KASLR processing is only used by the primary boot path, and complements the processing that takes place in __primary_switch(). Move the two parts together, to make the code easier to understand. Also, fix up a minor whitespace issue. Reviewed-by: Mark Rutland Signed-off-by: Ard Biesheuvel [will: fixed conflict with -rc3 due to lack of fd363bd417dd] Signed-off-by: Will Deacon --- arch/arm64/kernel/head.S | 69 ++++++++++++++++++++++++---------------- 1 file changed, 42 insertions(+), 27 deletions(-) diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index be02c5593ba6..5543068da3ae 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -222,9 +222,7 @@ ENTRY(stext) * the TCR will have been set. */ bl __cpu_setup // initialise processor - adr_l x27, __primary_switch // address to jump to after - // MMU has been enabled - b __enable_mmu + b __primary_switch ENDPROC(stext) /* @@ -453,7 +451,7 @@ __primary_switched: cbz x0, 0f // KASLR disabled? just proceed orr x23, x23, x0 // record KASLR offset ret x28 // we must enable KASLR, return - // to __enable_mmu() + // to __primary_switch() 0: #endif b start_kernel @@ -726,7 +724,6 @@ ENDPROC(__secondary_switched) * If it isn't, park the CPU */ 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 cmp x2, #ID_AA64MMFR0_TGRAN_SUPPORTED @@ -747,25 +744,6 @@ ENTRY(__enable_mmu) ic iallu dsb nsh isb -#ifdef CONFIG_RANDOMIZE_BASE - mov x19, x0 // preserve new SCTLR_EL1 value - blr x27 - - /* - * If we return here, we have a KASLR displacement in x23 which we need - * to take into account by discarding the current kernel mapping and - * creating a new one. - */ - msr sctlr_el1, x22 // disable the MMU - isb - bl __create_page_tables // recreate kernel mapping - - msr sctlr_el1, x19 // re-enable the MMU - isb - ic iallu // flush instructions fetched - dsb nsh // via old mapping - isb -#endif br x27 ENDPROC(__enable_mmu) @@ -775,11 +753,11 @@ __no_granule_support: 1: wfe wfi - b 1b + b 1b ENDPROC(__no_granule_support) -__primary_switch: #ifdef CONFIG_RELOCATABLE +__relocate_kernel: /* * Iterate over each entry in the relocation table, and apply the * relocations in place. @@ -801,8 +779,45 @@ __primary_switch: add x13, x13, x23 // relocate str x13, [x11, x23] b 0b +1: ret +ENDPROC(__relocate_kernel) +#endif -1: +__primary_switch: +#ifdef CONFIG_RANDOMIZE_BASE + mov x19, x0 // preserve new SCTLR_EL1 value + mrs x20, sctlr_el1 // preserve old SCTLR_EL1 value +#endif + + adr x27, 0f + b __enable_mmu +0: +#ifdef CONFIG_RELOCATABLE + bl __relocate_kernel +#ifdef CONFIG_RANDOMIZE_BASE + ldr x8, =__primary_switched + blr x8 + + /* + * If we return here, we have a KASLR displacement in x23 which we need + * to take into account by discarding the current kernel mapping and + * creating a new one. + */ + msr sctlr_el1, x20 // disable the MMU + isb + bl __create_page_tables // recreate kernel mapping + + tlbi vmalle1 // Remove any stale TLB entries + dsb nsh + + msr sctlr_el1, x19 // re-enable the MMU + isb + ic iallu // flush instructions fetched + dsb nsh // via old mapping + isb + + bl __relocate_kernel +#endif #endif ldr x8, =__primary_switched br x8 -- 2.25.1