16accb6b24
- 264 license table entries with exact download URLs (224/264 resolved) - Complete sources/ directory with all BitBake recipes - Build configuration: tqma6ul-multi-mba6ulx, spaetzle (musl) - Full traceability for Softwarefreigabeantrag - GCC 13.4.0, Linux 6.6.102, U-Boot 2023.04, musl 1.2.4 - License distribution: GPL-2.0 (24), MIT (23), GPL-2.0+ (18), BSD-3 (16)
237 lines
8.0 KiB
Diff
237 lines
8.0 KiB
Diff
From cb48d5d1592e63ebd0d4a3e300ef98e38e6306d7 Mon Sep 17 00:00:00 2001
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From: Richard Henderson <richard.henderson@linaro.org>
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Date: Wed, 28 Feb 2024 10:25:17 -1000
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Subject: [PATCH 4/5] linux-user: Rewrite target_shmat
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Handle combined host and guest alignment requirements.
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Handle host and guest page size differences.
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Handle SHM_EXEC.
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Upstream-Status: Submitted [https://www.mail-archive.com/qemu-devel@nongnu.org/msg1026793.html]
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Resolves: https://gitlab.com/qemu-project/qemu/-/issues/115
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Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
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---
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linux-user/mmap.c | 166 +++++++++++++++++++++++++++++++++++++---------
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1 file changed, 133 insertions(+), 33 deletions(-)
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diff --git a/linux-user/mmap.c b/linux-user/mmap.c
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index 18fb3aaf7..6a2f649bb 100644
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--- a/linux-user/mmap.c
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+++ b/linux-user/mmap.c
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@@ -1062,69 +1062,161 @@ static inline abi_ulong target_shmlba(CPUArchState *cpu_env)
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}
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#endif
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+#if defined(__arm__) || defined(__mips__) || defined(__sparc__)
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+#define HOST_FORCE_SHMLBA 1
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+#else
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+#define HOST_FORCE_SHMLBA 0
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+#endif
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+
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abi_ulong target_shmat(CPUArchState *cpu_env, int shmid,
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abi_ulong shmaddr, int shmflg)
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{
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CPUState *cpu = env_cpu(cpu_env);
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- abi_ulong raddr;
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struct shmid_ds shm_info;
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int ret;
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- abi_ulong shmlba;
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+ int h_pagesize;
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+ int t_shmlba, h_shmlba, m_shmlba;
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+ size_t t_len, h_len, m_len;
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/* shmat pointers are always untagged */
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- /* find out the length of the shared memory segment */
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+ /*
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+ * Because we can't use host shmat() unless the address is sufficiently
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+ * aligned for the host, we'll need to check both.
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+ * TODO: Could be fixed with softmmu.
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+ */
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+ t_shmlba = target_shmlba(cpu_env);
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+ h_pagesize = qemu_real_host_page_size();
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+ h_shmlba = (HOST_FORCE_SHMLBA ? SHMLBA : h_pagesize);
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+ m_shmlba = MAX(t_shmlba, h_shmlba);
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+
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+ if (shmaddr) {
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+ if (shmaddr & (m_shmlba - 1)) {
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+ if (shmflg & SHM_RND) {
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+ /*
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+ * The guest is allowing the kernel to round the address.
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+ * Assume that the guest is ok with us rounding to the
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+ * host required alignment too. Anyway if we don't, we'll
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+ * get an error from the kernel.
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+ */
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+ shmaddr &= ~(m_shmlba - 1);
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+ if (shmaddr == 0 && (shmflg & SHM_REMAP)) {
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+ return -TARGET_EINVAL;
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+ }
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+ } else {
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+ int require = TARGET_PAGE_SIZE;
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+#ifdef TARGET_FORCE_SHMLBA
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+ require = t_shmlba;
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+#endif
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+ /*
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+ * Include host required alignment, as otherwise we cannot
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+ * use host shmat at all.
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+ */
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+ require = MAX(require, h_shmlba);
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+ if (shmaddr & (require - 1)) {
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+ return -TARGET_EINVAL;
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+ }
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+ }
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+ }
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+ } else {
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+ if (shmflg & SHM_REMAP) {
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+ return -TARGET_EINVAL;
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+ }
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+ }
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+ /* All rounding now manually concluded. */
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+ shmflg &= ~SHM_RND;
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+
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+ /* Find out the length of the shared memory segment. */
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ret = get_errno(shmctl(shmid, IPC_STAT, &shm_info));
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if (is_error(ret)) {
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/* can't get length, bail out */
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return ret;
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}
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+ t_len = TARGET_PAGE_ALIGN(shm_info.shm_segsz);
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+ h_len = ROUND_UP(shm_info.shm_segsz, h_pagesize);
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+ m_len = MAX(t_len, h_len);
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- shmlba = target_shmlba(cpu_env);
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-
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- if (shmaddr & (shmlba - 1)) {
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- if (shmflg & SHM_RND) {
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- shmaddr &= ~(shmlba - 1);
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- } else {
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- return -TARGET_EINVAL;
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- }
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- }
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- if (!guest_range_valid_untagged(shmaddr, shm_info.shm_segsz)) {
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+ if (!guest_range_valid_untagged(shmaddr, m_len)) {
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return -TARGET_EINVAL;
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}
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WITH_MMAP_LOCK_GUARD() {
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- void *host_raddr;
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+ bool mapped = false;
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+ void *want, *test;
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abi_ulong last;
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- if (shmaddr) {
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- host_raddr = shmat(shmid, (void *)g2h_untagged(shmaddr), shmflg);
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+ if (!shmaddr) {
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+ shmaddr = mmap_find_vma(0, m_len, m_shmlba);
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+ if (shmaddr == -1) {
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+ return -TARGET_ENOMEM;
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+ }
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+ mapped = !reserved_va;
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+ } else if (shmflg & SHM_REMAP) {
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+ /*
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+ * If host page size > target page size, the host shmat may map
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+ * more memory than the guest expects. Reject a mapping that
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+ * would replace memory in the unexpected gap.
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+ * TODO: Could be fixed with softmmu.
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+ */
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+ if (t_len < h_len &&
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+ !page_check_range_empty(shmaddr + t_len,
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+ shmaddr + h_len - 1)) {
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+ return -TARGET_EINVAL;
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+ }
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} else {
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- abi_ulong mmap_start;
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+ if (!page_check_range_empty(shmaddr, shmaddr + m_len - 1)) {
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+ return -TARGET_EINVAL;
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+ }
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+ }
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- /* In order to use the host shmat, we need to honor host SHMLBA. */
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- mmap_start = mmap_find_vma(0, shm_info.shm_segsz,
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- MAX(SHMLBA, shmlba));
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+ /* All placement is now complete. */
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+ want = (void *)g2h_untagged(shmaddr);
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- if (mmap_start == -1) {
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- return -TARGET_ENOMEM;
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+ /*
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+ * Map anonymous pages across the entire range, then remap with
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+ * the shared memory. This is required for a number of corner
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+ * cases for which host and guest page sizes differ.
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+ */
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+ if (h_len != t_len) {
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+ int mmap_p = PROT_READ | (shmflg & SHM_RDONLY ? 0 : PROT_WRITE);
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+ int mmap_f = MAP_PRIVATE | MAP_ANONYMOUS
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+ | (reserved_va || (shmflg & SHM_REMAP)
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+ ? MAP_FIXED : MAP_FIXED_NOREPLACE);
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+
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+ test = mmap(want, m_len, mmap_p, mmap_f, -1, 0);
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+ if (unlikely(test != want)) {
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+ /* shmat returns EINVAL not EEXIST like mmap. */
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+ ret = (test == MAP_FAILED && errno != EEXIST
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+ ? get_errno(-1) : -TARGET_EINVAL);
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+ if (mapped) {
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+ do_munmap(want, m_len);
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+ }
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+ return ret;
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}
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- host_raddr = shmat(shmid, g2h_untagged(mmap_start),
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- shmflg | SHM_REMAP);
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+ mapped = true;
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}
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- if (host_raddr == (void *)-1) {
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- return get_errno(-1);
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+ if (reserved_va || mapped) {
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+ shmflg |= SHM_REMAP;
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+ }
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+ test = shmat(shmid, want, shmflg);
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+ if (test == MAP_FAILED) {
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+ ret = get_errno(-1);
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+ if (mapped) {
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+ do_munmap(want, m_len);
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+ }
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+ return ret;
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}
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- raddr = h2g(host_raddr);
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- last = raddr + shm_info.shm_segsz - 1;
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+ assert(test == want);
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- page_set_flags(raddr, last,
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+ last = shmaddr + m_len - 1;
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+ page_set_flags(shmaddr, last,
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PAGE_VALID | PAGE_RESET | PAGE_READ |
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- (shmflg & SHM_RDONLY ? 0 : PAGE_WRITE));
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+ (shmflg & SHM_RDONLY ? 0 : PAGE_WRITE) |
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+ (shmflg & SHM_EXEC ? PAGE_EXEC : 0));
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- shm_region_rm_complete(raddr, last);
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- shm_region_add(raddr, last);
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+ shm_region_rm_complete(shmaddr, last);
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+ shm_region_add(shmaddr, last);
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}
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/*
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@@ -1138,7 +1230,15 @@ abi_ulong target_shmat(CPUArchState *cpu_env, int shmid,
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tb_flush(cpu);
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}
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- return raddr;
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+ if (qemu_loglevel_mask(CPU_LOG_PAGE)) {
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+ FILE *f = qemu_log_trylock();
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+ if (f) {
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+ fprintf(f, "page layout changed following shmat\n");
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+ page_dump(f);
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+ qemu_log_unlock(f);
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+ }
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+ }
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+ return shmaddr;
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}
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abi_long target_shmdt(abi_ulong shmaddr)
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--
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2.34.1
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