Patchwork [2/6] mips_malta: correct reading MIPS revision at 0x1fc00010

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Submitter Leon Alrae
Date June 14, 2013, 7:30 a.m.
Message ID <1371195048-19618-3-git-send-email-leon.alrae@imgtec.com>
Download mbox | patch
Permalink /patch/251252/
State New
Headers show

Comments

Leon Alrae - June 14, 2013, 7:30 a.m.
From: Paul Burton <paul.burton@imgtec.com>

Rather than modifying the BIOS code at its original location, copy it
for the 0x1fc00000 region & modify the copy. This means the original
ROM code is correctly readable at 0x1e000010 whilst the MIPS revision
is readable at 0x1fc00010.

Additionally the code previously operated on target memory which would
later be overwritten by the BIOS image upon CPU reset if the -bios
argument was used to specify the BIOS image. This led to the written
MIPS revision being lost. Copying using rom_copy when -bios is used
fixes this issue.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
---
 hw/mips/mips_malta.c |   25 +++++++++++++++++--------
 1 files changed, 17 insertions(+), 8 deletions(-)
Andreas Färber - July 29, 2013, 4:33 a.m.
Am 14.06.2013 09:30, schrieb Leon Alrae:
> From: Paul Burton <paul.burton@imgtec.com>
> 
> Rather than modifying the BIOS code at its original location, copy it
> for the 0x1fc00000 region & modify the copy. This means the original
> ROM code is correctly readable at 0x1e000010 whilst the MIPS revision
> is readable at 0x1fc00010.
> 
> Additionally the code previously operated on target memory which would
> later be overwritten by the BIOS image upon CPU reset if the -bios
> argument was used to specify the BIOS image. This led to the written
> MIPS revision being lost. Copying using rom_copy when -bios is used
> fixes this issue.
> 
> Signed-off-by: Paul Burton <paul.burton@imgtec.com>
> Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
> ---
>  hw/mips/mips_malta.c |   25 +++++++++++++++++--------
>  1 files changed, 17 insertions(+), 8 deletions(-)

For some reason this commit breaks `make check`, please revert or fix.

Andreas

> 
> diff --git a/hw/mips/mips_malta.c b/hw/mips/mips_malta.c
> index 4def898..9117ae4 100644
> --- a/hw/mips/mips_malta.c
> +++ b/hw/mips/mips_malta.c
> @@ -789,7 +789,7 @@ void mips_malta_init(QEMUMachineInitArgs *args)
>      pflash_t *fl;
>      MemoryRegion *system_memory = get_system_memory();
>      MemoryRegion *ram = g_new(MemoryRegion, 1);
> -    MemoryRegion *bios, *bios_alias = g_new(MemoryRegion, 1);
> +    MemoryRegion *bios, *bios_copy = g_new(MemoryRegion, 1);
>      target_long bios_size = FLASH_SIZE;
>      int64_t kernel_entry;
>      PCIBus *pci_bus;
> @@ -929,14 +929,23 @@ void mips_malta_init(QEMUMachineInitArgs *args)
>  #endif
>      }
>  
> -    /* Map the BIOS at a 2nd physical location, as on the real board. */
> -    memory_region_init_alias(bios_alias, "bios.1fc", bios, 0, BIOS_SIZE);
> -    memory_region_add_subregion(system_memory, RESET_ADDRESS, bios_alias);
> +    /*
> +     * Map the BIOS at a 2nd physical location, as on the real board.
> +     * Copy it so that we can patch in the MIPS revision, which cannot be
> +     * handled by an overlapping region as the resulting ROM code subpage
> +     * regions are not executable.
> +     */
> +    memory_region_init_ram(bios_copy, "bios.1fc", BIOS_SIZE);
> +    if (!rom_copy(memory_region_get_ram_ptr(bios_copy),
> +                  FLASH_ADDRESS, bios_size)) {
> +        memcpy(memory_region_get_ram_ptr(bios_copy),
> +               memory_region_get_ram_ptr(bios), bios_size);
> +    }
> +    memory_region_set_readonly(bios_copy, true);
> +    memory_region_add_subregion(system_memory, RESET_ADDRESS, bios_copy);
>  
> -    /* Board ID = 0x420 (Malta Board with CoreLV)
> -       XXX: theoretically 0x1e000010 should map to flash and 0x1fc00010 should
> -       map to the board ID. */
> -    stl_p(memory_region_get_ram_ptr(bios) + 0x10, 0x00000420);
> +    /* Board ID = 0x420 (Malta Board with CoreLV) */
> +    stl_p(memory_region_get_ram_ptr(bios_copy) + 0x10, 0x00000420);
>  
>      /* Init internal devices */
>      cpu_mips_irq_init_cpu(env);
>

Patch

diff --git a/hw/mips/mips_malta.c b/hw/mips/mips_malta.c
index 4def898..9117ae4 100644
--- a/hw/mips/mips_malta.c
+++ b/hw/mips/mips_malta.c
@@ -789,7 +789,7 @@  void mips_malta_init(QEMUMachineInitArgs *args)
     pflash_t *fl;
     MemoryRegion *system_memory = get_system_memory();
     MemoryRegion *ram = g_new(MemoryRegion, 1);
-    MemoryRegion *bios, *bios_alias = g_new(MemoryRegion, 1);
+    MemoryRegion *bios, *bios_copy = g_new(MemoryRegion, 1);
     target_long bios_size = FLASH_SIZE;
     int64_t kernel_entry;
     PCIBus *pci_bus;
@@ -929,14 +929,23 @@  void mips_malta_init(QEMUMachineInitArgs *args)
 #endif
     }
 
-    /* Map the BIOS at a 2nd physical location, as on the real board. */
-    memory_region_init_alias(bios_alias, "bios.1fc", bios, 0, BIOS_SIZE);
-    memory_region_add_subregion(system_memory, RESET_ADDRESS, bios_alias);
+    /*
+     * Map the BIOS at a 2nd physical location, as on the real board.
+     * Copy it so that we can patch in the MIPS revision, which cannot be
+     * handled by an overlapping region as the resulting ROM code subpage
+     * regions are not executable.
+     */
+    memory_region_init_ram(bios_copy, "bios.1fc", BIOS_SIZE);
+    if (!rom_copy(memory_region_get_ram_ptr(bios_copy),
+                  FLASH_ADDRESS, bios_size)) {
+        memcpy(memory_region_get_ram_ptr(bios_copy),
+               memory_region_get_ram_ptr(bios), bios_size);
+    }
+    memory_region_set_readonly(bios_copy, true);
+    memory_region_add_subregion(system_memory, RESET_ADDRESS, bios_copy);
 
-    /* Board ID = 0x420 (Malta Board with CoreLV)
-       XXX: theoretically 0x1e000010 should map to flash and 0x1fc00010 should
-       map to the board ID. */
-    stl_p(memory_region_get_ram_ptr(bios) + 0x10, 0x00000420);
+    /* Board ID = 0x420 (Malta Board with CoreLV) */
+    stl_p(memory_region_get_ram_ptr(bios_copy) + 0x10, 0x00000420);
 
     /* Init internal devices */
     cpu_mips_irq_init_cpu(env);