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Diffstat (limited to 'arch/arm/include/asm/uaccess-asm.h')
-rw-r--r-- | arch/arm/include/asm/uaccess-asm.h | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/arch/arm/include/asm/uaccess-asm.h b/arch/arm/include/asm/uaccess-asm.h new file mode 100644 index 0000000000..65da32e1f1 --- /dev/null +++ b/arch/arm/include/asm/uaccess-asm.h @@ -0,0 +1,111 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef __ASM_UACCESS_ASM_H__ +#define __ASM_UACCESS_ASM_H__ + +#include <asm/asm-offsets.h> +#include <asm/domain.h> +#include <asm/page.h> +#include <asm/thread_info.h> + + .macro csdb +#ifdef CONFIG_THUMB2_KERNEL + .inst.w 0xf3af8014 +#else + .inst 0xe320f014 +#endif + .endm + + .macro check_uaccess, addr:req, size:req, limit:req, tmp:req, bad:req +#ifndef CONFIG_CPU_USE_DOMAINS + adds \tmp, \addr, #\size - 1 + sbcscc \tmp, \tmp, \limit + bcs \bad +#ifdef CONFIG_CPU_SPECTRE + movcs \addr, #0 + csdb +#endif +#endif + .endm + + .macro uaccess_mask_range_ptr, addr:req, size:req, limit:req, tmp:req +#ifdef CONFIG_CPU_SPECTRE + sub \tmp, \limit, #1 + subs \tmp, \tmp, \addr @ tmp = limit - 1 - addr + addhs \tmp, \tmp, #1 @ if (tmp >= 0) { + subshs \tmp, \tmp, \size @ tmp = limit - (addr + size) } + movlo \addr, #0 @ if (tmp < 0) addr = NULL + csdb +#endif + .endm + + .macro uaccess_disable, tmp, isb=1 +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + /* + * Whenever we re-enter userspace, the domains should always be + * set appropriately. + */ + mov \tmp, #DACR_UACCESS_DISABLE + mcr p15, 0, \tmp, c3, c0, 0 @ Set domain register + .if \isb + instr_sync + .endif +#endif + .endm + + .macro uaccess_enable, tmp, isb=1 +#ifdef CONFIG_CPU_SW_DOMAIN_PAN + /* + * Whenever we re-enter userspace, the domains should always be + * set appropriately. + */ + mov \tmp, #DACR_UACCESS_ENABLE + mcr p15, 0, \tmp, c3, c0, 0 + .if \isb + instr_sync + .endif +#endif + .endm + +#if defined(CONFIG_CPU_SW_DOMAIN_PAN) || defined(CONFIG_CPU_USE_DOMAINS) +#define DACR(x...) x +#else +#define DACR(x...) +#endif + + /* + * Save the address limit on entry to a privileged exception. + * + * If we are using the DACR for kernel access by the user accessors + * (CONFIG_CPU_USE_DOMAINS=y), always reset the DACR kernel domain + * back to client mode, whether or not \disable is set. + * + * If we are using SW PAN, set the DACR user domain to no access + * if \disable is set. + */ + .macro uaccess_entry, tsk, tmp0, tmp1, tmp2, disable + DACR( mrc p15, 0, \tmp0, c3, c0, 0) + DACR( str \tmp0, [sp, #SVC_DACR]) + .if \disable && IS_ENABLED(CONFIG_CPU_SW_DOMAIN_PAN) + /* kernel=client, user=no access */ + mov \tmp2, #DACR_UACCESS_DISABLE + mcr p15, 0, \tmp2, c3, c0, 0 + instr_sync + .elseif IS_ENABLED(CONFIG_CPU_USE_DOMAINS) + /* kernel=client */ + bic \tmp2, \tmp0, #domain_mask(DOMAIN_KERNEL) + orr \tmp2, \tmp2, #domain_val(DOMAIN_KERNEL, DOMAIN_CLIENT) + mcr p15, 0, \tmp2, c3, c0, 0 + instr_sync + .endif + .endm + + /* Restore the user access state previously saved by uaccess_entry */ + .macro uaccess_exit, tsk, tmp0, tmp1 + DACR( ldr \tmp0, [sp, #SVC_DACR]) + DACR( mcr p15, 0, \tmp0, c3, c0, 0) + .endm + +#undef DACR + +#endif /* __ASM_UACCESS_ASM_H__ */ |