diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index bae5edf348ef..e6bd9e79737c 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -56,8 +56,19 @@ void __raw_readsl(const volatile void __iomem *addr, void *data, int longlen); * the bus. Rather than special-case the machine, just let the compiler * generate the access for CPUs prior to ARMv6. */ -#define __raw_readw(a) (__chk_io_ptr(a), *(volatile unsigned short __force *)(a)) -#define __raw_writew(v,a) ((void)(__chk_io_ptr(a), *(volatile unsigned short __force *)(a) = (v))) +#define __raw_writew __raw_writew +static __no_kasan_or_inline void __raw_writew(u16 val, volatile void __iomem *addr) +{ + __chk_io_ptr(addr); + *(volatile unsigned short __force *)addr = val; +} + +#define __raw_readw __raw_readw +static __no_kasan_or_inline u16 __raw_readw(const volatile void __iomem *addr) +{ + __chk_io_ptr(addr); + return *(const volatile unsigned short __force *)addr; +} #else /* * When running under a hypervisor, we want to avoid I/O accesses with diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index ef6a657c8d13..a3d050ce9b79 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -567,7 +567,7 @@ ENTRY(__switch_to) @ are using KASAN mov_l r2, KASAN_SHADOW_OFFSET add r2, r2, ip, lsr #KASAN_SHADOW_SCALE_SHIFT - ldr r2, [r2] + ldrb r2, [r2] #endif #endif diff --git a/arch/arm/kernel/hibernate.c b/arch/arm/kernel/hibernate.c index 38a90a3d12b2..231a76af09a0 100644 --- a/arch/arm/kernel/hibernate.c +++ b/arch/arm/kernel/hibernate.c @@ -21,6 +21,7 @@ #include #include #include +#include #include "reboot.h" int pfn_is_nosave(unsigned long pfn) @@ -82,6 +83,15 @@ static void notrace arch_restore_image(void *unused) { struct pbe *pbe; + /* + * With CONFIG_CPU_TTBR0_PAN enabled, TTBCR.EPD0 is set to block + * TTBR0 page-table walks. The identity mapping used here lives at + * low (user-space) virtual addresses and is only reachable via + * TTBR0, so re-enable those walks before switching page tables. + * On non-PAN kernels this is a no-op. + */ + if (IS_ENABLED(CONFIG_CPU_TTBR0_PAN)) + uaccess_save_and_enable(); cpu_switch_mm(idmap_pgd, &init_mm); for (pbe = restore_pblist; pbe; pbe = pbe->next) copy_page(pbe->orig_address, pbe->address); diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c index 4a833e89782a..70403e968d2a 100644 --- a/arch/arm/mm/idmap.c +++ b/arch/arm/mm/idmap.c @@ -11,6 +11,7 @@ #include #include #include +#include /* * Note: accesses outside of the kernel image and the identity map area @@ -133,6 +134,17 @@ early_initcall(init_static_idmap); */ void setup_mm_for_reboot(void) { + /* + * With CONFIG_CPU_TTBR0_PAN enabled, TTBCR.EPD0 is set whenever + * user-space access is disabled in order to block TTBR0 page-table + * walks. The identity mapping lives at low (user-space) virtual + * addresses and can only be reached via TTBR0, so we must re-enable + * those walks before switching page tables. On non-PAN kernels this + * is a no-op. + */ + if (IS_ENABLED(CONFIG_CPU_TTBR0_PAN)) + uaccess_save_and_enable(); + /* Switch to the identity mapping. */ cpu_switch_mm(idmap_pgd, &init_mm); local_flush_bp_all();