arch/arm64/include/asm/asm-uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_ASM_UACCESS_H
   3 #define __ASM_ASM_UACCESS_H
   4
   5 #include <asm/alternative.h>
   6 #include <asm/kernel-pgtable.h>
   7 #include <asm/mmu.h>
   8 #include <asm/sysreg.h>
   9 #include <asm/assembler.h>
  10
  11 /*
  12  * User access enabling/disabling macros.
  13  */
  14 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
  15         .macro  __uaccess_ttbr0_disable, tmp1
  16         mrs     \tmp1, ttbr1_el1                // swapper_pg_dir
  17         bic     \tmp1, \tmp1, #TTBR_ASID_MASK
  18         add     \tmp1, \tmp1, #SWAPPER_DIR_SIZE // reserved_ttbr0 at the end of swapper_pg_dir
  19         msr     ttbr0_el1, \tmp1                // set reserved TTBR0_EL1
  20         isb
  21         sub     \tmp1, \tmp1, #SWAPPER_DIR_SIZE
  22         msr     ttbr1_el1, \tmp1                // set reserved ASID
  23         isb
  24         .endm
  25
  26         .macro  __uaccess_ttbr0_enable, tmp1, tmp2
  27         get_thread_info \tmp1
  28         ldr     \tmp1, [\tmp1, #TSK_TI_TTBR0]   // load saved TTBR0_EL1
  29         mrs     \tmp2, ttbr1_el1
  30         extr    \tmp2, \tmp2, \tmp1, #48
  31         ror     \tmp2, \tmp2, #16
  32         msr     ttbr1_el1, \tmp2                // set the active ASID
  33         isb
  34         msr     ttbr0_el1, \tmp1                // set the non-PAN TTBR0_EL1
  35         isb
  36         .endm
  37
  38         .macro  uaccess_ttbr0_disable, tmp1, tmp2
  39 alternative_if_not ARM64_HAS_PAN
  40         save_and_disable_irq \tmp2              // avoid preemption
  41         __uaccess_ttbr0_disable \tmp1
  42         restore_irq \tmp2
  43 alternative_else_nop_endif
  44         .endm
  45
  46         .macro  uaccess_ttbr0_enable, tmp1, tmp2, tmp3
  47 alternative_if_not ARM64_HAS_PAN
  48         save_and_disable_irq \tmp3              // avoid preemption
  49         __uaccess_ttbr0_enable \tmp1, \tmp2
  50         restore_irq \tmp3
  51 alternative_else_nop_endif
  52         .endm
  53 #else
  54         .macro  uaccess_ttbr0_disable, tmp1, tmp2
  55         .endm
  56
  57         .macro  uaccess_ttbr0_enable, tmp1, tmp2, tmp3
  58         .endm
  59 #endif
  60
  61 /*
  62  * These macros are no-ops when UAO is present.
  63  */
  64         .macro  uaccess_disable_not_uao, tmp1, tmp2
  65         uaccess_ttbr0_disable \tmp1, \tmp2
  66 alternative_if ARM64_ALT_PAN_NOT_UAO
  67         SET_PSTATE_PAN(1)
  68 alternative_else_nop_endif
  69         .endm
  70
  71         .macro  uaccess_enable_not_uao, tmp1, tmp2, tmp3
  72         uaccess_ttbr0_enable \tmp1, \tmp2, \tmp3
  73 alternative_if ARM64_ALT_PAN_NOT_UAO
  74         SET_PSTATE_PAN(0)
  75 alternative_else_nop_endif
  76         .endm
  77
  78 /*
  79  * Remove the address tag from a virtual address, if present.
  80  */
  81         .macro  clear_address_tag, dst, addr
  82         tst     \addr, #(1 << 55)
  83         bic     \dst, \addr, #(0xff << 56)
  84         csel    \dst, \dst, \addr, eq
  85         .endm
  86
  87 #endif