LXR linux/arch/powerpc/include/asm/book3s/32/kup.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _ASM_POWERPC_BOOK3S_32_KUP_H
   3#define _ASM_POWERPC_BOOK3S_32_KUP_H
   4
   5#include <asm/book3s/32/mmu-hash.h>
   6
   7#ifdef __ASSEMBLY__
   8
   9.macro kuep_update_sr   gpr1, gpr2              /* NEVER use r0 as gpr2 due to addis */
  10101:    mtsrin  \gpr1, \gpr2
  11        addi    \gpr1, \gpr1, 0x111             /* next VSID */
  12        rlwinm  \gpr1, \gpr1, 0, 0xf0ffffff     /* clear VSID overflow */
  13        addis   \gpr2, \gpr2, 0x1000            /* address of next segment */
  14        bdnz    101b
  15        isync
  16.endm
  17
  18.macro kuep_lock        gpr1, gpr2
  19#ifdef CONFIG_PPC_KUEP
  20        li      \gpr1, NUM_USER_SEGMENTS
  21        li      \gpr2, 0
  22        mtctr   \gpr1
  23        mfsrin  \gpr1, \gpr2
  24        oris    \gpr1, \gpr1, SR_NX@h           /* set Nx */
  25        kuep_update_sr \gpr1, \gpr2
  26#endif
  27.endm
  28
  29.macro kuep_unlock      gpr1, gpr2
  30#ifdef CONFIG_PPC_KUEP
  31        li      \gpr1, NUM_USER_SEGMENTS
  32        li      \gpr2, 0
  33        mtctr   \gpr1
  34        mfsrin  \gpr1, \gpr2
  35        rlwinm  \gpr1, \gpr1, 0, ~SR_NX         /* Clear Nx */
  36        kuep_update_sr \gpr1, \gpr2
  37#endif
  38.endm
  39
  40#ifdef CONFIG_PPC_KUAP
  41
  42.macro kuap_update_sr   gpr1, gpr2, gpr3        /* NEVER use r0 as gpr2 due to addis */
  43101:    mtsrin  \gpr1, \gpr2
  44        addi    \gpr1, \gpr1, 0x111             /* next VSID */
  45        rlwinm  \gpr1, \gpr1, 0, 0xf0ffffff     /* clear VSID overflow */
  46        addis   \gpr2, \gpr2, 0x1000            /* address of next segment */
  47        cmplw   \gpr2, \gpr3
  48        blt-    101b
  49        isync
  50.endm
  51
  52.macro kuap_save_and_lock       sp, thread, gpr1, gpr2, gpr3
  53        lwz     \gpr2, KUAP(\thread)
  54        rlwinm. \gpr3, \gpr2, 28, 0xf0000000
  55        stw     \gpr2, STACK_REGS_KUAP(\sp)
  56        beq+    102f
  57        li      \gpr1, 0
  58        stw     \gpr1, KUAP(\thread)
  59        mfsrin  \gpr1, \gpr2
  60        oris    \gpr1, \gpr1, SR_KS@h   /* set Ks */
  61        kuap_update_sr  \gpr1, \gpr2, \gpr3
  62102:
  63.endm
  64
  65.macro kuap_restore     sp, current, gpr1, gpr2, gpr3
  66        lwz     \gpr2, STACK_REGS_KUAP(\sp)
  67        rlwinm. \gpr3, \gpr2, 28, 0xf0000000
  68        stw     \gpr2, THREAD + KUAP(\current)
  69        beq+    102f
  70        mfsrin  \gpr1, \gpr2
  71        rlwinm  \gpr1, \gpr1, 0, ~SR_KS /* Clear Ks */
  72        kuap_update_sr  \gpr1, \gpr2, \gpr3
  73102:
  74.endm
  75
  76.macro kuap_check       current, gpr
  77#ifdef CONFIG_PPC_KUAP_DEBUG
  78        lwz     \gpr2, KUAP(thread)
  79999:    twnei   \gpr, 0
  80        EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE)
  81#endif
  82.endm
  83
  84#endif /* CONFIG_PPC_KUAP */
  85
  86#else /* !__ASSEMBLY__ */
  87
  88#ifdef CONFIG_PPC_KUAP
  89
  90#include <linux/sched.h>
  91
  92static inline void kuap_update_sr(u32 sr, u32 addr, u32 end)
  93{
  94        barrier();      /* make sure thread.kuap is updated before playing with SRs */
  95        while (addr < end) {
  96                mtsrin(sr, addr);
  97                sr += 0x111;            /* next VSID */
  98                sr &= 0xf0ffffff;       /* clear VSID overflow */
  99                addr += 0x10000000;     /* address of next segment */
 100        }
 101        isync();        /* Context sync required after mtsrin() */
 102}
 103
 104static inline void allow_user_access(void __user *to, const void __user *from, u32 size)
 105{
 106        u32 addr, end;
 107
 108        if (__builtin_constant_p(to) && to == NULL)
 109                return;
 110
 111        addr = (__force u32)to;
 112
 113        if (!addr || addr >= TASK_SIZE || !size)
 114                return;
 115
 116        end = min(addr + size, TASK_SIZE);
 117        current->thread.kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf);
 118        kuap_update_sr(mfsrin(addr) & ~SR_KS, addr, end);       /* Clear Ks */
 119}
 120
 121static inline void prevent_user_access(void __user *to, const void __user *from, u32 size)
 122{
 123        u32 addr = (__force u32)to;
 124        u32 end = min(addr + size, TASK_SIZE);
 125
 126        if (!addr || addr >= TASK_SIZE || !size)
 127                return;
 128
 129        current->thread.kuap = 0;
 130        kuap_update_sr(mfsrin(addr) | SR_KS, addr, end);        /* set Ks */
 131}
 132
 133static inline bool bad_kuap_fault(struct pt_regs *regs, bool is_write)
 134{
 135        if (!is_write)
 136                return false;
 137
 138        return WARN(!regs->kuap, "Bug: write fault blocked by segment registers !");
 139}
 140
 141#endif /* CONFIG_PPC_KUAP */
 142
 143#endif /* __ASSEMBLY__ */
 144
 145#endif /* _ASM_POWERPC_BOOK3S_32_KUP_H */
 146