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[PATCH 22/43] semihosting: Split out semihost_sys_read
From: |
Richard Henderson |
Subject: |
[PATCH 22/43] semihosting: Split out semihost_sys_read |
Date: |
Sat, 30 Apr 2022 06:29:11 -0700 |
Split out the non-ARM specific portions of SYS_READ to a
reusable function. This handles all GuestFD. Isolate the
curious ARM-specific return value processing to a new
callback, common_semi_rw_cb.
Note that gdb_do_syscall %x reads target_ulong, not int.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
include/semihosting/guestfd.h | 3 ++
semihosting/arm-compat-semi.c | 84 ++++++++---------------------------
semihosting/guestfd.c | 75 +++++++++++++++++++++++++++++++
3 files changed, 97 insertions(+), 65 deletions(-)
diff --git a/include/semihosting/guestfd.h b/include/semihosting/guestfd.h
index c38b1d3657..568d55fd32 100644
--- a/include/semihosting/guestfd.h
+++ b/include/semihosting/guestfd.h
@@ -56,4 +56,7 @@ void semihost_sys_open(CPUState *cs, gdb_syscall_complete_cb
complete,
void semihost_sys_close(CPUState *cs, gdb_syscall_complete_cb complete, int
fd);
+void semihost_sys_read(CPUState *cs, gdb_syscall_complete_cb complete,
+ int fd, target_ulong buf, target_ulong len);
+
#endif /* SEMIHOSTING_GUESTFD_H */
diff --git a/semihosting/arm-compat-semi.c b/semihosting/arm-compat-semi.c
index f20e84c4f0..2c6c2dd0d0 100644
--- a/semihosting/arm-compat-semi.c
+++ b/semihosting/arm-compat-semi.c
@@ -232,7 +232,6 @@ static void common_semi_cb(CPUState *cs, target_ulong ret,
target_ulong err)
target_ulong reg0 = common_semi_arg(cs, 0);
switch (reg0) {
case TARGET_SYS_WRITE:
- case TARGET_SYS_READ:
ret = common_semi_syscall_len - ret;
break;
case TARGET_SYS_SEEK:
@@ -245,6 +244,24 @@ static void common_semi_cb(CPUState *cs, target_ulong ret,
target_ulong err)
common_semi_set_ret(cs, ret);
}
+/*
+ * SYS_READ and SYS_WRITE always return the number of bytes not read/written.
+ * There is no error condition, other than returning the original length.
+ */
+static void common_semi_rw_cb(CPUState *cs, target_ulong ret, target_ulong err)
+{
+ /* Recover the original length from the third argument. */
+ CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
+ target_ulong args = common_semi_arg(cs, 1);
+ target_ulong arg2;
+ GET_ARG(2);
+
+ if (err) {
+ ret = 0; /* error: no bytes transmitted */
+ }
+ common_semi_set_ret(cs, arg2 - ret);
+}
+
/*
* Return an address in target memory of 64 bytes where the remote
* gdb should write its stat struct. (The format of this structure
@@ -278,8 +295,6 @@ common_semi_flen_cb(CPUState *cs, target_ulong ret,
target_ulong err)
*/
typedef void sys_writefn(CPUState *cs, GuestFD *gf,
target_ulong buf, uint32_t len);
-typedef void sys_readfn(CPUState *cs, GuestFD *gf,
- target_ulong buf, uint32_t len);
typedef void sys_isattyfn(CPUState *cs, GuestFD *gf);
typedef void sys_seekfn(CPUState *cs, GuestFD *gf, target_ulong offset);
typedef void sys_flenfn(CPUState *cs, GuestFD *gf);
@@ -302,26 +317,6 @@ static void host_writefn(CPUState *cs, GuestFD *gf,
common_semi_cb(cs, len - ret, 0);
}
-static void host_readfn(CPUState *cs, GuestFD *gf,
- target_ulong buf, uint32_t len)
-{
- CPUArchState *env = cs->env_ptr;
- uint32_t ret = 0;
- char *s = lock_user(VERIFY_WRITE, buf, len, 0);
- (void) env; /* Used in arm softmmu lock_user implicitly */
- if (s) {
- do {
- ret = read(gf->hostfd, s, len);
- } while (ret == -1 && errno == EINTR);
- unlock_user(s, buf, len);
- if (ret == (uint32_t)-1) {
- ret = 0;
- }
- }
- /* Return bytes not read, on error as well. */
- common_semi_cb(cs, len - ret, 0);
-}
-
static void host_isattyfn(CPUState *cs, GuestFD *gf)
{
common_semi_cb(cs, isatty(gf->hostfd), 0);
@@ -351,13 +346,6 @@ static void gdb_writefn(CPUState *cs, GuestFD *gf,
gdb_do_syscall(common_semi_cb, "write,%x,%x,%x", gf->hostfd, buf, len);
}
-static void gdb_readfn(CPUState *cs, GuestFD *gf,
- target_ulong buf, uint32_t len)
-{
- common_semi_syscall_len = len;
- gdb_do_syscall(common_semi_cb, "read,%x,%x,%x", gf->hostfd, buf, len);
-}
-
static void gdb_isattyfn(CPUState *cs, GuestFD *gf)
{
gdb_do_syscall(common_semi_cb, "isatty,%x", gf->hostfd);
@@ -398,30 +386,6 @@ static void staticfile_writefn(CPUState *cs, GuestFD *gf,
common_semi_cb(cs, -1, EBADF);
}
-static void staticfile_readfn(CPUState *cs, GuestFD *gf,
- target_ulong buf, uint32_t len)
-{
- CPUArchState *env = cs->env_ptr;
- uint32_t i = 0;
- char *s;
-
- (void) env; /* Used in arm softmmu lock_user implicitly */
- s = lock_user(VERIFY_WRITE, buf, len, 0);
- if (s) {
- for (i = 0; i < len; i++) {
- if (gf->staticfile.off >= gf->staticfile.len) {
- break;
- }
- s[i] = gf->staticfile.data[gf->staticfile.off];
- gf->staticfile.off++;
- }
- unlock_user(s, buf, len);
- }
-
- /* Return number of bytes not read */
- common_semi_cb(cs, len - i, 0);
-}
-
static void staticfile_isattyfn(CPUState *cs, GuestFD *gf)
{
common_semi_cb(cs, 0, 0);
@@ -440,7 +404,6 @@ static void staticfile_flenfn(CPUState *cs, GuestFD *gf)
typedef struct GuestFDFunctions {
sys_writefn *writefn;
- sys_readfn *readfn;
sys_isattyfn *isattyfn;
sys_seekfn *seekfn;
sys_flenfn *flenfn;
@@ -449,21 +412,18 @@ typedef struct GuestFDFunctions {
static const GuestFDFunctions guestfd_fns[] = {
[GuestFDHost] = {
.writefn = host_writefn,
- .readfn = host_readfn,
.isattyfn = host_isattyfn,
.seekfn = host_seekfn,
.flenfn = host_flenfn,
},
[GuestFDGDB] = {
.writefn = gdb_writefn,
- .readfn = gdb_readfn,
.isattyfn = gdb_isattyfn,
.seekfn = gdb_seekfn,
.flenfn = gdb_flenfn,
},
[GuestFDStatic] = {
.writefn = staticfile_writefn,
- .readfn = staticfile_readfn,
.isattyfn = staticfile_isattyfn,
.seekfn = staticfile_seekfn,
.flenfn = staticfile_flenfn,
@@ -582,13 +542,7 @@ void do_common_semihosting(CPUState *cs)
GET_ARG(0);
GET_ARG(1);
GET_ARG(2);
- len = arg2;
-
- gf = get_guestfd(arg0);
- if (!gf) {
- goto do_badf;
- }
- guestfd_fns[gf->type].readfn(cs, gf, arg1, len);
+ semihost_sys_read(cs, common_semi_rw_cb, arg0, arg1, arg2);
break;
case TARGET_SYS_READC:
diff --git a/semihosting/guestfd.c b/semihosting/guestfd.c
index c26b1c677e..057e384d65 100644
--- a/semihosting/guestfd.c
+++ b/semihosting/guestfd.c
@@ -303,3 +303,78 @@ void semihost_sys_close(CPUState *cs,
gdb_syscall_complete_cb complete, int fd)
}
do_dealloc_guestfd(gf);
}
+
+static void gdb_read(CPUState *cs, gdb_syscall_complete_cb complete,
+ GuestFD *gf, target_ulong buf, target_ulong len)
+{
+ gdb_do_syscall(complete, "read,%x,%x,%x",
+ (target_ulong)gf->hostfd, buf, len);
+}
+
+static void host_read(CPUState *cs, gdb_syscall_complete_cb complete,
+ GuestFD *gf, target_ulong buf, target_ulong len)
+{
+ CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
+ void *ptr = lock_user(VERIFY_WRITE, buf, len, 0);
+ ssize_t ret;
+
+ if (!ptr) {
+ complete(cs, -1, EFAULT);
+ return;
+ }
+ do {
+ ret = read(gf->hostfd, ptr, len);
+ } while (ret == -1 && errno == EINTR);
+ if (ret == -1) {
+ complete(cs, -1, errno);
+ unlock_user(ptr, buf, 0);
+ } else {
+ complete(cs, ret, 0);
+ unlock_user(ptr, buf, ret);
+ }
+}
+
+static void staticfile_read(CPUState *cs, gdb_syscall_complete_cb complete,
+ GuestFD *gf, target_ulong buf, target_ulong len)
+{
+ CPUArchState *env G_GNUC_UNUSED = cs->env_ptr;
+ target_ulong rest = gf->staticfile.len - gf->staticfile.off;
+ void *ptr;
+
+ if (len > rest) {
+ len = rest;
+ }
+ ptr = lock_user(VERIFY_WRITE, buf, len, 0);
+ if (!ptr) {
+ complete(cs, -1, EFAULT);
+ return;
+ }
+ memcpy(ptr, gf->staticfile.data + gf->staticfile.off, len);
+ gf->staticfile.off += len;
+ complete(cs, len, 0);
+ unlock_user(ptr, buf, len);
+}
+
+void semihost_sys_read(CPUState *cs, gdb_syscall_complete_cb complete,
+ int fd, target_ulong buf, target_ulong len)
+{
+ GuestFD *gf = get_guestfd(fd);
+
+ if (!gf) {
+ complete(cs, -1, EBADF);
+ return;
+ }
+ switch (gf->type) {
+ case GuestFDGDB:
+ gdb_read(cs, complete, gf, buf, len);
+ break;
+ case GuestFDHost:
+ host_read(cs, complete, gf, buf, len);
+ break;
+ case GuestFDStatic:
+ staticfile_read(cs, complete, gf, buf, len);
+ break;
+ default:
+ g_assert_not_reached();
+ }
+}
--
2.34.1
- [PATCH 05/43] semihosting: Add target_strlen for softmmu-uaccess.h, (continued)
- [PATCH 05/43] semihosting: Add target_strlen for softmmu-uaccess.h, Richard Henderson, 2022/04/30
- [PATCH 20/43] semihosting: Split out semihost_sys_open, Richard Henderson, 2022/04/30
- [PATCH 19/43] semihosting: Move GET_ARG/SET_ARG earlier in the file, Richard Henderson, 2022/04/30
- [PATCH 24/43] semihosting: Bound length for semihost_sys_{read, write}, Richard Henderson, 2022/04/30
- [PATCH 33/43] gdbstub: Widen gdb_syscall_complete_cb return value, Richard Henderson, 2022/04/30
- [PATCH 35/43] target/m68k: Make semihosting system only, Richard Henderson, 2022/04/30
- [PATCH 39/43] target/m68k: Remove EXCP_HALT_INSN, Richard Henderson, 2022/04/30
- [PATCH 09/43] semihosting: Return void from do_common_semihosting, Richard Henderson, 2022/04/30
- [PATCH 15/43] semihosting: Split is_64bit_semihosting per target, Richard Henderson, 2022/04/30
- [PATCH 14/43] semihosting: Use struct gdb_stat in common_semi_flen_cb, Richard Henderson, 2022/04/30
- [PATCH 22/43] semihosting: Split out semihost_sys_read,
Richard Henderson <=
- [PATCH 21/43] semihosting: Split out semihost_sys_close, Richard Henderson, 2022/04/30
- [PATCH 26/43] semihosting: Split out semihost_sys_isatty, Richard Henderson, 2022/04/30
- [PATCH 27/43] semihosting: Split out semihost_sys_flen, Richard Henderson, 2022/04/30
- [PATCH 30/43] semihosting: Split out semihost_sys_system, Richard Henderson, 2022/04/30
- [PATCH 31/43] semihosting: Create semihost_sys_{stat,fstat}, Richard Henderson, 2022/04/30
- [PATCH 38/43] target/m68k: Enable semihosting for non-coldfire, Richard Henderson, 2022/04/30
- [PATCH 34/43] target/m68k: Eliminate m68k_semi_is_fseek, Richard Henderson, 2022/04/30
- [PATCH 16/43] semihosting: Split common_semi_flen_buf per target, Richard Henderson, 2022/04/30
- [PATCH 23/43] semihosting: Split out semihost_sys_write, Richard Henderson, 2022/04/30
- [PATCH 28/43] semihosting: Split out semihost_sys_remove, Richard Henderson, 2022/04/30