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[PATCH v3 05/49] semihosting: Add target_strlen for softmmu-uaccess.h
From: |
Richard Henderson |
Subject: |
[PATCH v3 05/49] semihosting: Add target_strlen for softmmu-uaccess.h |
Date: |
Fri, 20 May 2022 17:03:16 -0700 |
Mirror the interface of the user-only function of the same name.
Use probe_access_flags for the common case of ram, and
cpu_memory_rw_debug for the uncommon case of mmio.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
v3: Use probe_access_flags (pmm)
---
include/semihosting/softmmu-uaccess.h | 3 ++
semihosting/uaccess.c | 49 +++++++++++++++++++++++++++
2 files changed, 52 insertions(+)
diff --git a/include/semihosting/softmmu-uaccess.h
b/include/semihosting/softmmu-uaccess.h
index 03300376d3..4f08dfc098 100644
--- a/include/semihosting/softmmu-uaccess.h
+++ b/include/semihosting/softmmu-uaccess.h
@@ -53,4 +53,7 @@ void softmmu_unlock_user(CPUArchState *env, void *p,
target_ulong addr, target_ulong len);
#define unlock_user(s, args, len) softmmu_unlock_user(env, s, args, len)
+ssize_t softmmu_strlen_user(CPUArchState *env, target_ulong addr);
+#define target_strlen(p) softmmu_strlen_user(env, p)
+
#endif /* SEMIHOSTING_SOFTMMU_UACCESS_H */
diff --git a/semihosting/uaccess.c b/semihosting/uaccess.c
index 0d3b32b75d..51019b79ff 100644
--- a/semihosting/uaccess.c
+++ b/semihosting/uaccess.c
@@ -8,6 +8,7 @@
*/
#include "qemu/osdep.h"
+#include "exec/exec-all.h"
#include "semihosting/softmmu-uaccess.h"
void *softmmu_lock_user(CPUArchState *env, target_ulong addr,
@@ -23,6 +24,54 @@ void *softmmu_lock_user(CPUArchState *env, target_ulong addr,
return p;
}
+ssize_t softmmu_strlen_user(CPUArchState *env, target_ulong addr)
+{
+ int mmu_idx = cpu_mmu_index(env, false);
+ size_t len = 0;
+
+ while (1) {
+ size_t left_in_page;
+ int flags;
+ void *h;
+
+ /* Find the number of bytes remaining in the page. */
+ left_in_page = -(addr | TARGET_PAGE_MASK);
+
+ flags = probe_access_flags(env, addr, MMU_DATA_LOAD,
+ mmu_idx, true, &h, 0);
+ if (flags & TLB_INVALID_MASK) {
+ return -1;
+ }
+ if (flags & TLB_MMIO) {
+ do {
+ uint8_t c;
+ if (cpu_memory_rw_debug(env_cpu(env), addr, &c, 1, 0)) {
+ return -1;
+ }
+ if (c == 0) {
+ return len;
+ }
+ addr++;
+ len++;
+ if (len > INT32_MAX) {
+ return -1;
+ }
+ } while (--left_in_page != 0);
+ } else {
+ char *p = memchr(h, 0, left_in_page);
+ if (p) {
+ len += p - (char *)h;
+ return len <= INT32_MAX ? (ssize_t)len : -1;
+ }
+ addr += left_in_page;
+ len += left_in_page;
+ if (len > INT32_MAX) {
+ return -1;
+ }
+ }
+ }
+}
+
char *softmmu_lock_user_string(CPUArchState *env, target_ulong addr)
{
/* TODO: Make this something that isn't fixed size. */
--
2.34.1
- [PATCH v3 02/49] semihosting: Return failure from softmmu-uaccess.h functions, (continued)
- [PATCH v3 02/49] semihosting: Return failure from softmmu-uaccess.h functions, Richard Henderson, 2022/05/20
- [PATCH v3 10/49] semihosting: Clean up common_semi_flen_cb, Richard Henderson, 2022/05/20
- [PATCH v3 06/49] semihosting: Simplify softmmu_lock_user_string, Richard Henderson, 2022/05/20
- [PATCH v3 08/49] semihosting: Inline set_swi_errno into common_semi_cb, Richard Henderson, 2022/05/20
- [PATCH v3 09/49] semihosting: Adjust error checking in common_semi_cb, Richard Henderson, 2022/05/20
- [PATCH v3 05/49] semihosting: Add target_strlen for softmmu-uaccess.h,
Richard Henderson <=
- [PATCH v3 11/49] semihosting: Clean up common_semi_open_cb, Richard Henderson, 2022/05/20
- [PATCH v3 07/49] semihosting: Split out guestfd.c, Richard Henderson, 2022/05/20
- [PATCH v3 04/49] semihosting: Move softmmu-uaccess.h functions out of line, Richard Henderson, 2022/05/20
- [PATCH v3 13/49] semihosting: Move common-semi.h to include/semihosting/, Richard Henderson, 2022/05/20
- [PATCH v3 24/49] semihosting: Split out semihost_sys_close, Richard Henderson, 2022/05/20
- [PATCH v3 16/49] include/exec: Define errno values in gdbstub.h, Richard Henderson, 2022/05/20