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1770b2f2d3
probe_access_flags() as it is today uses probe_access_full(), which in
turn uses probe_access_internal() with size = 0. probe_access_internal()
then uses the size to call the tlb_fill() callback for the given CPU.
This size param ('fault_size' as probe_access_internal() calls it) is
ignored by most existing .tlb_fill callback implementations, e.g.
arm_cpu_tlb_fill(), ppc_cpu_tlb_fill(), x86_cpu_tlb_fill() and
mips_cpu_tlb_fill() to name a few.
But RISC-V riscv_cpu_tlb_fill() actually uses it. The 'size' parameter
is used to check for PMP (Physical Memory Protection) access. This is
necessary because PMP does not make any guarantees about all the bytes
of the same page having the same permissions, i.e. the same page can
have different PMP properties, so we're forced to make sub-page range
checks. To allow RISC-V emulation to do a probe_acess_flags() that
covers PMP, we need to either add a 'size' param to the existing
probe_acess_flags() or create a new interface (e.g.
probe_access_range_flags).
There are quite a few probe_* APIs already, so let's add a 'size' param
to probe_access_flags() and re-use this API. This is done by open coding
what probe_access_full() does inside probe_acess_flags() and passing the
'size' param to probe_acess_internal(). Existing probe_access_flags()
callers use size = 0 to not change their current API usage. 'size' is
asserted to enforce single page access like probe_access() already does.
No behavioral changes intended.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-Id: <20230223234427.521114-2-dbarboza@ventanamicro.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
91 lines
2.3 KiB
C
91 lines
2.3 KiB
C
/*
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* Helper routines to provide target memory access for semihosting
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* syscalls in system emulation mode.
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*
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* Copyright (c) 2007 CodeSourcery.
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*
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* This code is licensed under the GPL
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*/
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#include "qemu/osdep.h"
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#include "exec/exec-all.h"
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#include "semihosting/softmmu-uaccess.h"
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void *softmmu_lock_user(CPUArchState *env, target_ulong addr,
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target_ulong len, bool copy)
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{
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void *p = malloc(len);
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if (p && copy) {
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if (cpu_memory_rw_debug(env_cpu(env), addr, p, len, 0)) {
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free(p);
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p = NULL;
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}
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}
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return p;
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}
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ssize_t softmmu_strlen_user(CPUArchState *env, target_ulong addr)
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{
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int mmu_idx = cpu_mmu_index(env, false);
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size_t len = 0;
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while (1) {
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size_t left_in_page;
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int flags;
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void *h;
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/* Find the number of bytes remaining in the page. */
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left_in_page = TARGET_PAGE_SIZE - (addr & ~TARGET_PAGE_MASK);
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flags = probe_access_flags(env, addr, 0, MMU_DATA_LOAD,
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mmu_idx, true, &h, 0);
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if (flags & TLB_INVALID_MASK) {
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return -1;
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}
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if (flags & TLB_MMIO) {
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do {
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uint8_t c;
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if (cpu_memory_rw_debug(env_cpu(env), addr, &c, 1, 0)) {
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return -1;
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}
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if (c == 0) {
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return len;
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}
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addr++;
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len++;
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if (len > INT32_MAX) {
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return -1;
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}
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} while (--left_in_page != 0);
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} else {
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char *p = memchr(h, 0, left_in_page);
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if (p) {
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len += p - (char *)h;
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return len <= INT32_MAX ? (ssize_t)len : -1;
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}
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addr += left_in_page;
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len += left_in_page;
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if (len > INT32_MAX) {
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return -1;
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}
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}
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}
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}
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char *softmmu_lock_user_string(CPUArchState *env, target_ulong addr)
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{
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ssize_t len = softmmu_strlen_user(env, addr);
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if (len < 0) {
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return NULL;
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}
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return softmmu_lock_user(env, addr, len + 1, true);
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}
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void softmmu_unlock_user(CPUArchState *env, void *p,
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target_ulong addr, target_ulong len)
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{
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if (len) {
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cpu_memory_rw_debug(env_cpu(env), addr, p, len, 1);
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}
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free(p);
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}
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