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9e2e6042a7
Commit2139619bca("riscv: mmap with PROT_WRITE but no PROT_READ is invalid") made mmap() return EINVAL if PROT_WRITE was set wihtout PROT_READ with the justification that a write-only PTE is considered a reserved PTE permission bit pattern in the privileged spec. This check is unnecessary since we let VM_WRITE imply VM_READ on RISC-V, and it is inconsistent with other architectures that don't support write-only PTEs, creating a potential software portability issue. Just remove the check altogether and let PROT_WRITE imply PROT_READ as is the case on other architectures. Note that this also allows PROT_WRITE|PROT_EXEC mappings which were disallowed prior to the aforementioned commit; PROT_READ is implied in such mappings as well. Fixes:2139619bca("riscv: mmap with PROT_WRITE but no PROT_READ is invalid") Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Andrew Bresticker <abrestic@rivosinc.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220915193702.2201018-3-abrestic@rivosinc.com/ Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
72 lines
2.3 KiB
C
72 lines
2.3 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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* Copyright (C) 2014 Darius Rad <darius@bluespec.com>
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* Copyright (C) 2017 SiFive
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*/
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#include <linux/syscalls.h>
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#include <asm/unistd.h>
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#include <asm/cacheflush.h>
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#include <asm-generic/mman-common.h>
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static long riscv_sys_mmap(unsigned long addr, unsigned long len,
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unsigned long prot, unsigned long flags,
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unsigned long fd, off_t offset,
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unsigned long page_shift_offset)
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{
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if (unlikely(offset & (~PAGE_MASK >> page_shift_offset)))
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return -EINVAL;
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return ksys_mmap_pgoff(addr, len, prot, flags, fd,
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offset >> (PAGE_SHIFT - page_shift_offset));
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}
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#ifdef CONFIG_64BIT
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SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
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unsigned long, prot, unsigned long, flags,
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unsigned long, fd, off_t, offset)
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{
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return riscv_sys_mmap(addr, len, prot, flags, fd, offset, 0);
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}
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#endif
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#if defined(CONFIG_32BIT) || defined(CONFIG_COMPAT)
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SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
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unsigned long, prot, unsigned long, flags,
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unsigned long, fd, off_t, offset)
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{
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/*
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* Note that the shift for mmap2 is constant (12),
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* regardless of PAGE_SIZE
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*/
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return riscv_sys_mmap(addr, len, prot, flags, fd, offset, 12);
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}
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#endif
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/*
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* Allows the instruction cache to be flushed from userspace. Despite RISC-V
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* having a direct 'fence.i' instruction available to userspace (which we
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* can't trap!), that's not actually viable when running on Linux because the
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* kernel might schedule a process on another hart. There is no way for
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* userspace to handle this without invoking the kernel (as it doesn't know the
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* thread->hart mappings), so we've defined a RISC-V specific system call to
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* flush the instruction cache.
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*
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* sys_riscv_flush_icache() is defined to flush the instruction cache over an
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* address range, with the flush applying to either all threads or just the
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* caller. We don't currently do anything with the address range, that's just
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* in there for forwards compatibility.
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*/
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SYSCALL_DEFINE3(riscv_flush_icache, uintptr_t, start, uintptr_t, end,
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uintptr_t, flags)
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{
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/* Check the reserved flags. */
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if (unlikely(flags & ~SYS_RISCV_FLUSH_ICACHE_ALL))
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return -EINVAL;
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flush_icache_mm(current->mm, flags & SYS_RISCV_FLUSH_ICACHE_LOCAL);
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return 0;
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}
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