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authorRichard Henderson <richard.henderson@linaro.org>2021-02-12 10:48:32 -0800
committerPeter Maydell <peter.maydell@linaro.org>2021-02-16 11:04:52 +0000
commitd9c5858570a57f374b71216c5da39ee381fa92f5 (patch)
tree993ffb46c24da50b9b88ab1269a889ab994ccd58
parent8ba4bca570ace1e60614a0808631a517cf5df67a (diff)
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tcg: Introduce target-specific page data for user-only
This data can be allocated by page_alloc_target_data() and released by page_set_flags(start, end, prot | PAGE_RESET). This data will be used to hold tag memory for AArch64 MTE. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20210212184902.1251044-2-richard.henderson@linaro.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
-rw-r--r--accel/tcg/translate-all.c28
-rw-r--r--include/exec/cpu-all.h42
-rw-r--r--linux-user/mmap.c4
-rw-r--r--linux-user/syscall.c4
4 files changed, 69 insertions, 9 deletions
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 81d4c83..bba9c8e 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -114,6 +114,7 @@ typedef struct PageDesc {
unsigned int code_write_count;
#else
unsigned long flags;
+ void *target_data;
#endif
#ifndef CONFIG_USER_ONLY
QemuSpin lock;
@@ -2740,6 +2741,7 @@ int page_get_flags(target_ulong address)
void page_set_flags(target_ulong start, target_ulong end, int flags)
{
target_ulong addr, len;
+ bool reset_target_data;
/* This function should never be called with addresses outside the
guest address space. If this assert fires, it probably indicates
@@ -2754,6 +2756,8 @@ void page_set_flags(target_ulong start, target_ulong end, int flags)
if (flags & PAGE_WRITE) {
flags |= PAGE_WRITE_ORG;
}
+ reset_target_data = !(flags & PAGE_VALID) || (flags & PAGE_RESET);
+ flags &= ~PAGE_RESET;
for (addr = start, len = end - start;
len != 0;
@@ -2767,10 +2771,34 @@ void page_set_flags(target_ulong start, target_ulong end, int flags)
p->first_tb) {
tb_invalidate_phys_page(addr, 0);
}
+ if (reset_target_data && p->target_data) {
+ g_free(p->target_data);
+ p->target_data = NULL;
+ }
p->flags = flags;
}
}
+void *page_get_target_data(target_ulong address)
+{
+ PageDesc *p = page_find(address >> TARGET_PAGE_BITS);
+ return p ? p->target_data : NULL;
+}
+
+void *page_alloc_target_data(target_ulong address, size_t size)
+{
+ PageDesc *p = page_find(address >> TARGET_PAGE_BITS);
+ void *ret = NULL;
+
+ if (p->flags & PAGE_VALID) {
+ ret = p->target_data;
+ if (!ret) {
+ p->target_data = ret = g_malloc0(size);
+ }
+ }
+ return ret;
+}
+
int page_check_range(target_ulong start, target_ulong len, int flags)
{
PageDesc *p;
diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index babf0a8..6421892 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -256,15 +256,21 @@ extern intptr_t qemu_host_page_mask;
#define PAGE_EXEC 0x0004
#define PAGE_BITS (PAGE_READ | PAGE_WRITE | PAGE_EXEC)
#define PAGE_VALID 0x0008
-/* original state of the write flag (used when tracking self-modifying
- code */
+/*
+ * Original state of the write flag (used when tracking self-modifying code)
+ */
#define PAGE_WRITE_ORG 0x0010
-/* Invalidate the TLB entry immediately, helpful for s390x
- * Low-Address-Protection. Used with PAGE_WRITE in tlb_set_page_with_attrs() */
-#define PAGE_WRITE_INV 0x0040
+/*
+ * Invalidate the TLB entry immediately, helpful for s390x
+ * Low-Address-Protection. Used with PAGE_WRITE in tlb_set_page_with_attrs()
+ */
+#define PAGE_WRITE_INV 0x0020
+/* For use with page_set_flags: page is being replaced; target_data cleared. */
+#define PAGE_RESET 0x0040
+
#if defined(CONFIG_BSD) && defined(CONFIG_USER_ONLY)
/* FIXME: Code that sets/uses this is broken and needs to go away. */
-#define PAGE_RESERVED 0x0020
+#define PAGE_RESERVED 0x0100
#endif
/* Target-specific bits that will be used via page_get_flags(). */
#define PAGE_TARGET_1 0x0080
@@ -279,6 +285,30 @@ int walk_memory_regions(void *, walk_memory_regions_fn);
int page_get_flags(target_ulong address);
void page_set_flags(target_ulong start, target_ulong end, int flags);
int page_check_range(target_ulong start, target_ulong len, int flags);
+
+/**
+ * page_alloc_target_data(address, size)
+ * @address: guest virtual address
+ * @size: size of data to allocate
+ *
+ * Allocate @size bytes of out-of-band data to associate with the
+ * guest page at @address. If the page is not mapped, NULL will
+ * be returned. If there is existing data associated with @address,
+ * no new memory will be allocated.
+ *
+ * The memory will be freed when the guest page is deallocated,
+ * e.g. with the munmap system call.
+ */
+void *page_alloc_target_data(target_ulong address, size_t size);
+
+/**
+ * page_get_target_data(address)
+ * @address: guest virtual address
+ *
+ * Return any out-of-bound memory assocated with the guest page
+ * at @address, as per page_alloc_target_data.
+ */
+void *page_get_target_data(target_ulong address);
#endif
CPUArchState *cpu_copy(CPUArchState *env);
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 1c9faef..ac0624f 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -599,6 +599,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot,
}
}
the_end1:
+ page_flags |= PAGE_RESET;
page_set_flags(start, start + len, page_flags);
the_end:
trace_target_mmap_complete(start);
@@ -794,7 +795,8 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size,
new_addr = h2g(host_addr);
prot = page_get_flags(old_addr);
page_set_flags(old_addr, old_addr + old_size, 0);
- page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
+ page_set_flags(new_addr, new_addr + new_size,
+ prot | PAGE_VALID | PAGE_RESET);
}
tb_invalidate_phys_range(new_addr, new_addr + new_size);
mmap_unlock();
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 36b0901..0c2d660 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -4643,8 +4643,8 @@ static inline abi_ulong do_shmat(CPUArchState *cpu_env,
raddr=h2g((unsigned long)host_raddr);
page_set_flags(raddr, raddr + shm_info.shm_segsz,
- PAGE_VALID | PAGE_READ |
- ((shmflg & SHM_RDONLY)? 0 : PAGE_WRITE));
+ PAGE_VALID | PAGE_RESET | PAGE_READ |
+ (shmflg & SHM_RDONLY ? 0 : PAGE_WRITE));
for (i = 0; i < N_SHM_REGIONS; i++) {
if (!shm_regions[i].in_use) {