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2e17430858
When pointer masking is enabled for userspace, the kernel can accept tagged pointers as arguments to some system calls. Allow this by untagging the pointers in access_ok() and the uaccess routines. The uaccess routines must peform untagging in software because U-mode and S-mode have entirely separate pointer masking configurations. In fact, hardware may not even implement pointer masking for S-mode. Since the number of tag bits is variable, untagged_addr_remote() needs to know what PMLEN to use for the remote mm. Therefore, the pointer masking mode must be the same for all threads sharing an mm. Enforce this with a lock flag in the mm context, as x86 does for LAM. The flag gets reset in init_new_context() during fork(), as the new mm is no longer multithreaded. Reviewed-by: Charlie Jenkins <charlie@rivosinc.com> Tested-by: Charlie Jenkins <charlie@rivosinc.com> Signed-off-by: Samuel Holland <samuel.holland@sifive.com> Link: https://lore.kernel.org/r/20241016202814.4061541-6-samuel.holland@sifive.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
45 lines
1 KiB
C
45 lines
1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2012 Regents of the University of California
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*/
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#ifndef _ASM_RISCV_MMU_H
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#define _ASM_RISCV_MMU_H
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#ifndef __ASSEMBLY__
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typedef struct {
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#ifndef CONFIG_MMU
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unsigned long end_brk;
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#else
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atomic_long_t id;
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#endif
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void *vdso;
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#ifdef CONFIG_SMP
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/* A local icache flush is needed before user execution can resume. */
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cpumask_t icache_stale_mask;
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/* Force local icache flush on all migrations. */
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bool force_icache_flush;
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#endif
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#ifdef CONFIG_BINFMT_ELF_FDPIC
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unsigned long exec_fdpic_loadmap;
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unsigned long interp_fdpic_loadmap;
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#endif
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unsigned long flags;
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#ifdef CONFIG_RISCV_ISA_SUPM
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u8 pmlen;
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#endif
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} mm_context_t;
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/* Lock the pointer masking mode because this mm is multithreaded */
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#define MM_CONTEXT_LOCK_PMLEN 0
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#define cntx2asid(cntx) ((cntx) & SATP_ASID_MASK)
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#define cntx2version(cntx) ((cntx) & ~SATP_ASID_MASK)
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void __meminit create_pgd_mapping(pgd_t *pgdp, uintptr_t va, phys_addr_t pa, phys_addr_t sz,
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pgprot_t prot);
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_RISCV_MMU_H */
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