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[Qemu-devel] [PATCH 2/2] acpi-build: don't access unaligned addresses
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] [PATCH 2/2] acpi-build: don't access unaligned addresses |
Date: |
Mon, 10 Mar 2014 21:43:23 +0200 |
casting an unaligned address to e.g.
uint32_t can trigger undefined behaviour in C.
Replace cast + assignment with memcpy.
Reported-by: Peter Maydell <address@hidden>
Signed-off-by: Michael S. Tsirkin <address@hidden>
---
hw/i386/acpi-build.c | 31 ++++++++++++++++---------------
1 file changed, 16 insertions(+), 15 deletions(-)
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index b667d31..e08f514 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -466,9 +466,15 @@ static void acpi_align_size(GArray *blob, unsigned align)
g_array_set_size(blob, ROUND_UP(acpi_data_len(blob), align));
}
-/* Get pointer within table in a safe manner */
-#define ACPI_BUILD_PTR(table, size, off, type) \
- ((type *)(acpi_data_get_ptr(table, size, off, sizeof(type))))
+/* Set a value within table in a safe manner */
+#define ACPI_BUILD_SET_LE(table, size, off, bits, val) \
+ do { \
+ uint64_t ACPI_BUILD_SET_LE_val = le_bswap(val, bits); \
+ memcpy(acpi_data_get_ptr(table, size, off, \
+ (bits) / BITS_PER_BYTE), \
+ &ACPI_BUILD_SET_LE_val, \
+ (bits) / BITS_PER_BYTE); \
+ } while (0)
static inline void *acpi_data_get_ptr(uint8_t *table_data, unsigned table_size,
unsigned off, unsigned size)
@@ -974,22 +980,17 @@ static void build_pci_bus_end(PCIBus *bus, void
*bus_state)
static void patch_pci_windows(PcPciInfo *pci, uint8_t *start, unsigned size)
{
- *ACPI_BUILD_PTR(start, size, acpi_pci32_start[0], uint32_t) =
- cpu_to_le32(pci->w32.begin);
+ ACPI_BUILD_SET_LE(start, size, acpi_pci32_start[0], 32, pci->w32.begin);
- *ACPI_BUILD_PTR(start, size, acpi_pci32_end[0], uint32_t) =
- cpu_to_le32(pci->w32.end - 1);
+ ACPI_BUILD_SET_LE(start, size, acpi_pci32_end[0], 32, pci->w32.end - 1);
if (pci->w64.end || pci->w64.begin) {
- *ACPI_BUILD_PTR(start, size, acpi_pci64_valid[0], uint8_t) = 1;
- *ACPI_BUILD_PTR(start, size, acpi_pci64_start[0], uint64_t) =
- cpu_to_le64(pci->w64.begin);
- *ACPI_BUILD_PTR(start, size, acpi_pci64_end[0], uint64_t) =
- cpu_to_le64(pci->w64.end - 1);
- *ACPI_BUILD_PTR(start, size, acpi_pci64_length[0], uint64_t) =
- cpu_to_le64(pci->w64.end - pci->w64.begin);
+ ACPI_BUILD_SET_LE(start, size, acpi_pci64_valid[0], 8, 1);
+ ACPI_BUILD_SET_LE(start, size, acpi_pci64_start[0], 64,
pci->w64.begin);
+ ACPI_BUILD_SET_LE(start, size, acpi_pci64_end[0], 64, pci->w64.end -
1);
+ ACPI_BUILD_SET_LE(start, size, acpi_pci64_length[0], 64, pci->w64.end
- pci->w64.begin);
} else {
- *ACPI_BUILD_PTR(start, size, acpi_pci64_valid[0], uint8_t) = 0;
+ ACPI_BUILD_SET_LE(start, size, acpi_pci64_valid[0], 8, 0);
}
}
--
MST