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197 lines
4.6 KiB
197 lines
4.6 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#ifndef _ASM_POWERPC_BOOK3S_32_KUP_H |
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#define _ASM_POWERPC_BOOK3S_32_KUP_H |
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#include <asm/bug.h> |
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#include <asm/book3s/32/mmu-hash.h> |
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#ifdef __ASSEMBLY__ |
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.macro kuep_update_sr gpr1, gpr2 /* NEVER use r0 as gpr2 due to addis */ |
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101: mtsrin \gpr1, \gpr2 |
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addi \gpr1, \gpr1, 0x111 /* next VSID */ |
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rlwinm \gpr1, \gpr1, 0, 0xf0ffffff /* clear VSID overflow */ |
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addis \gpr2, \gpr2, 0x1000 /* address of next segment */ |
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bdnz 101b |
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isync |
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.endm |
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.macro kuep_lock gpr1, gpr2 |
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#ifdef CONFIG_PPC_KUEP |
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li \gpr1, NUM_USER_SEGMENTS |
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li \gpr2, 0 |
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mtctr \gpr1 |
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mfsrin \gpr1, \gpr2 |
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oris \gpr1, \gpr1, SR_NX@h /* set Nx */ |
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kuep_update_sr \gpr1, \gpr2 |
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#endif |
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.endm |
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.macro kuep_unlock gpr1, gpr2 |
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#ifdef CONFIG_PPC_KUEP |
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li \gpr1, NUM_USER_SEGMENTS |
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li \gpr2, 0 |
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mtctr \gpr1 |
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mfsrin \gpr1, \gpr2 |
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rlwinm \gpr1, \gpr1, 0, ~SR_NX /* Clear Nx */ |
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kuep_update_sr \gpr1, \gpr2 |
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#endif |
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.endm |
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#ifdef CONFIG_PPC_KUAP |
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.macro kuap_update_sr gpr1, gpr2, gpr3 /* NEVER use r0 as gpr2 due to addis */ |
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101: mtsrin \gpr1, \gpr2 |
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addi \gpr1, \gpr1, 0x111 /* next VSID */ |
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rlwinm \gpr1, \gpr1, 0, 0xf0ffffff /* clear VSID overflow */ |
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addis \gpr2, \gpr2, 0x1000 /* address of next segment */ |
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cmplw \gpr2, \gpr3 |
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blt- 101b |
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isync |
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.endm |
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.macro kuap_save_and_lock sp, thread, gpr1, gpr2, gpr3 |
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lwz \gpr2, KUAP(\thread) |
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rlwinm. \gpr3, \gpr2, 28, 0xf0000000 |
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stw \gpr2, STACK_REGS_KUAP(\sp) |
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beq+ 102f |
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li \gpr1, 0 |
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stw \gpr1, KUAP(\thread) |
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mfsrin \gpr1, \gpr2 |
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oris \gpr1, \gpr1, SR_KS@h /* set Ks */ |
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kuap_update_sr \gpr1, \gpr2, \gpr3 |
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102: |
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.endm |
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.macro kuap_restore sp, current, gpr1, gpr2, gpr3 |
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lwz \gpr2, STACK_REGS_KUAP(\sp) |
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rlwinm. \gpr3, \gpr2, 28, 0xf0000000 |
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stw \gpr2, THREAD + KUAP(\current) |
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beq+ 102f |
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mfsrin \gpr1, \gpr2 |
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rlwinm \gpr1, \gpr1, 0, ~SR_KS /* Clear Ks */ |
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kuap_update_sr \gpr1, \gpr2, \gpr3 |
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102: |
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.endm |
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.macro kuap_check current, gpr |
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#ifdef CONFIG_PPC_KUAP_DEBUG |
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lwz \gpr, THREAD + KUAP(\current) |
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999: twnei \gpr, 0 |
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EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE) |
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#endif |
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.endm |
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#endif /* CONFIG_PPC_KUAP */ |
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#else /* !__ASSEMBLY__ */ |
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#ifdef CONFIG_PPC_KUAP |
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#include <linux/sched.h> |
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static inline void kuap_update_sr(u32 sr, u32 addr, u32 end) |
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{ |
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addr &= 0xf0000000; /* align addr to start of segment */ |
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barrier(); /* make sure thread.kuap is updated before playing with SRs */ |
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while (addr < end) { |
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mtsrin(sr, addr); |
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sr += 0x111; /* next VSID */ |
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sr &= 0xf0ffffff; /* clear VSID overflow */ |
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addr += 0x10000000; /* address of next segment */ |
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} |
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isync(); /* Context sync required after mtsrin() */ |
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} |
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static __always_inline void allow_user_access(void __user *to, const void __user *from, |
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u32 size, unsigned long dir) |
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{ |
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u32 addr, end; |
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BUILD_BUG_ON(!__builtin_constant_p(dir)); |
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BUILD_BUG_ON(dir & ~KUAP_READ_WRITE); |
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if (!(dir & KUAP_WRITE)) |
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return; |
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addr = (__force u32)to; |
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if (unlikely(addr >= TASK_SIZE || !size)) |
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return; |
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end = min(addr + size, TASK_SIZE); |
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current->thread.kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf); |
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kuap_update_sr(mfsrin(addr) & ~SR_KS, addr, end); /* Clear Ks */ |
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} |
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static __always_inline void prevent_user_access(void __user *to, const void __user *from, |
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u32 size, unsigned long dir) |
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{ |
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u32 addr, end; |
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BUILD_BUG_ON(!__builtin_constant_p(dir)); |
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if (dir & KUAP_CURRENT_WRITE) { |
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u32 kuap = current->thread.kuap; |
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if (unlikely(!kuap)) |
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return; |
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addr = kuap & 0xf0000000; |
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end = kuap << 28; |
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} else if (dir & KUAP_WRITE) { |
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addr = (__force u32)to; |
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end = min(addr + size, TASK_SIZE); |
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if (unlikely(addr >= TASK_SIZE || !size)) |
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return; |
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} else { |
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return; |
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} |
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current->thread.kuap = 0; |
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kuap_update_sr(mfsrin(addr) | SR_KS, addr, end); /* set Ks */ |
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} |
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static inline unsigned long prevent_user_access_return(void) |
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{ |
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unsigned long flags = current->thread.kuap; |
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unsigned long addr = flags & 0xf0000000; |
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unsigned long end = flags << 28; |
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void __user *to = (__force void __user *)addr; |
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if (flags) |
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prevent_user_access(to, to, end - addr, KUAP_READ_WRITE); |
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return flags; |
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} |
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static inline void restore_user_access(unsigned long flags) |
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{ |
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unsigned long addr = flags & 0xf0000000; |
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unsigned long end = flags << 28; |
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void __user *to = (__force void __user *)addr; |
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if (flags) |
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allow_user_access(to, to, end - addr, KUAP_READ_WRITE); |
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} |
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static inline bool |
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bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) |
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{ |
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unsigned long begin = regs->kuap & 0xf0000000; |
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unsigned long end = regs->kuap << 28; |
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if (!is_write) |
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return false; |
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return WARN(address < begin || address >= end, |
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"Bug: write fault blocked by segment registers !"); |
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} |
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#endif /* CONFIG_PPC_KUAP */ |
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#endif /* __ASSEMBLY__ */ |
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#endif /* _ASM_POWERPC_BOOK3S_32_KUP_H */
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