[Qemu-devel] [PATCH 06/11] sun4m: avoid structure holes spotted by pahole

[Blue Swirl]

Edited report from pahole on amd64 host:
struct sun4c_hwdef {
...
        uint8_t                    nvram_machine_id;     /*   112     1 */

        /* XXX 1 byte hole, try to pack */
...
        /* size: 136, cachelines: 3 */
        /* sum members: 135, holes: 1, sum holes: 1 */
        /* last cacheline: 8 bytes */
};      /* definitions: 1 */

struct sun4d_hwdef {
...
        uint8_t                    nvram_machine_id;     /*   128     1 */

        /* XXX 1 byte hole, try to pack */
...
        /* size: 152, cachelines: 3 */
        /* sum members: 151, holes: 1, sum holes: 1 */
        /* last cacheline: 24 bytes */
};      /* definitions: 1 */

struct sun4m_hwdef {
...
        uint8_t                    nvram_machine_id;     /*   260     1 */

        /* XXX 1 byte hole, try to pack */

        uint16_t                   machine_id;           /*   262     2 */
        uint32_t                   iommu_version;        /*   264     4 */

        /* XXX 4 bytes hole, try to pack */
...
        /* size: 288, cachelines: 5 */
        /* sum members: 283, holes: 2, sum holes: 5 */
        /* last cacheline: 32 bytes */
};      /* definitions: 1 */

Fix by rearranging the structures to avoid padding.

Signed-off-by: Blue Swirl <address@hidden>
---
 hw/sun4m.c |   20 ++++++++++----------
 1 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/hw/sun4m.c b/hw/sun4m.c
index df3aa32..5afb1b1 100644
--- a/hw/sun4m.c
+++ b/hw/sun4m.c
@@ -97,12 +97,12 @@ struct sun4m_hwdef {
         target_phys_addr_t reg_base, vram_base;
     } vsimm[MAX_VSIMMS];
     target_phys_addr_t ecc_base;
-    uint32_t ecc_version;
-    uint8_t nvram_machine_id;
-    uint16_t machine_id;
-    uint32_t iommu_version;
     uint64_t max_mem;
     const char * const default_cpu_model;
+    uint32_t ecc_version;
+    uint32_t iommu_version;
+    uint16_t machine_id;
+    uint8_t nvram_machine_id;
 };

 #define MAX_IOUNITS 5
@@ -115,11 +115,11 @@ struct sun4d_hwdef {
     target_phys_addr_t ledma_base, le_base;
     target_phys_addr_t tcx_base;
     target_phys_addr_t sbi_base;
-    uint8_t nvram_machine_id;
-    uint16_t machine_id;
-    uint32_t iounit_version;
     uint64_t max_mem;
     const char * const default_cpu_model;
+    uint32_t iounit_version;
+    uint16_t machine_id;
+    uint8_t nvram_machine_id;
 };

 struct sun4c_hwdef {
@@ -128,11 +128,11 @@ struct sun4c_hwdef {
     target_phys_addr_t serial_base, fd_base;
     target_phys_addr_t idreg_base, dma_base, esp_base, le_base;
     target_phys_addr_t tcx_base, aux1_base;
-    uint8_t nvram_machine_id;
-    uint16_t machine_id;
-    uint32_t iommu_version;
     uint64_t max_mem;
     const char * const default_cpu_model;
+    uint32_t iommu_version;
+    uint16_t machine_id;
+    uint8_t nvram_machine_id;
 };

 int DMA_get_channel_mode (int nchan)
-- 
1.6.2.4

0006-sun4m-avoid-structure-holes-spotted-by-pahole.patch
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