Re: [Qemu-devel] [PATCH] mips_malta: provide ememsize env variable to kernels

[Aurelien Jarno <aurelien@aurel32.net>]

On 2015-05-25 14:21, Paul Burton wrote:
> Commit 94c2b6aff43c (mips_malta: support up to 2GiB RAM) provided
> support for using over 256MB of RAM with the MIPS Malta board, including
> capping the memsize variable that QEMUs pseudo-bootloader provides to
> the kernel at 256MB in order to match YAMON. It didn't however provide
> the ememsize variable which kernels supporting memory outside of the
> unmapped address spaces (ie. EVA or highmem) may use to determine the
> true size of the RAM present in the system.
> 
> Set ememsize to the size of RAM so that such kernels may use all
> available memory without the user having to manually specifying its size
> & location.
> 
> Signed-off-by: Paul Burton <paul.burton@imgtec.com>
> Cc: Aurelien Jarno <aurelien@aurel32.net>
> Cc: Leon Alrae <leon.alrae@imgtec.com>
> ---
> Note that in order for Linux kernels to make use of all memory
> automatically when using highmem rather than EVA, the following patchset
> is required:
> 
>   http://www.linux-mips.org/archives/linux-mips/2015-05/msg00377.html
> ---
>  hw/mips/mips_malta.c | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/hw/mips/mips_malta.c b/hw/mips/mips_malta.c
> index 482250d..affdb04 100644
> --- a/hw/mips/mips_malta.c
> +++ b/hw/mips/mips_malta.c
> @@ -97,7 +97,7 @@ typedef struct {
>  static ISADevice *pit;
>  
>  static struct _loaderparams {
> -    int ram_size;
> +    int ram_size, ram_low_size;
>      const char *kernel_filename;
>      const char *kernel_cmdline;
>      const char *initrd_filename;
> @@ -641,8 +641,8 @@ static void write_bootloader (CPUMIPSState *env, uint8_t *base,
>      stl_p(p++, 0x34a50000 | (ENVP_ADDR & 0xffff));               /* ori a1, a1, low(ENVP_ADDR) */
>      stl_p(p++, 0x3c060000 | (((ENVP_ADDR + 8) >> 16) & 0xffff)); /* lui a2, high(ENVP_ADDR + 8) */
>      stl_p(p++, 0x34c60000 | ((ENVP_ADDR + 8) & 0xffff));         /* ori a2, a2, low(ENVP_ADDR + 8) */
> -    stl_p(p++, 0x3c070000 | (loaderparams.ram_size >> 16));     /* lui a3, high(ram_size) */
> -    stl_p(p++, 0x34e70000 | (loaderparams.ram_size & 0xffff));  /* ori a3, a3, low(ram_size) */
> +    stl_p(p++, 0x3c070000 | (loaderparams.ram_low_size >> 16));     /* lui a3, high(ram_low_size) */
> +    stl_p(p++, 0x34e70000 | (loaderparams.ram_low_size & 0xffff));  /* ori a3, a3, low(ram_low_size) */
>  
>      /* Load BAR registers as done by YAMON */
>      stl_p(p++, 0x3c09b400);                                      /* lui t1, 0xb400 */
> @@ -851,8 +851,10 @@ static int64_t load_kernel (void)
>      }
>  
>      prom_set(prom_buf, prom_index++, "memsize");
> -    prom_set(prom_buf, prom_index++, "%i",
> -             MIN(loaderparams.ram_size, 256 << 20));
> +    prom_set(prom_buf, prom_index++, "%u", loaderparams.ram_low_size);
> +
> +    prom_set(prom_buf, prom_index++, "ememsize");
> +    prom_set(prom_buf, prom_index++, "%u", loaderparams.ram_size);
>  
>      prom_set(prom_buf, prom_index++, "modetty0");
>      prom_set(prom_buf, prom_index++, "38400n8r");
> @@ -1054,7 +1056,8 @@ void mips_malta_init(MachineState *machine)
>          }
>  
>          /* Write a small bootloader to the flash location. */
> -        loaderparams.ram_size = ram_low_size;
> +        loaderparams.ram_size = ram_size;
> +        loaderparams.ram_low_size = ram_low_size;
>          loaderparams.kernel_filename = kernel_filename;
>          loaderparams.kernel_cmdline = kernel_cmdline;
>          loaderparams.initrd_filename = initrd_filename;

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net