On Thu, Dec 21, 2017 at 10:00:59PM +0100, Mathieu Malaterre wrote:
> From: Marcin Nowakowski <marcin.nowakowski@xxxxxxxx>
>
> Change 73fbc1eba7ff added a fix to ensure that the memory range between
Please refer to commits with e.g. commit 73fbc1eba7ff ("MIPS: fix
mem=X@Y commandline processing").
> PHYS_OFFSET and low memory address specified by mem= cmdline argument is
> not later processed by free_all_bootmem.
> This change was incorrect for systems where the commandline specifies
> more than 1 mem argument, as it will cause all memory between
> PHYS_OFFSET and each of the memory offsets to be marked as reserved,
> which results in parts of the RAM marked as reserved (Creator CI20's
> u-boot has a default commandline argument 'mem=256M@0x0
> mem=768M@0x30000000').
>
> Change the behaviour to ensure that only the range between PHYS_OFFSET
> and the lowest start address of the memories is marked as protected.
>
> This change also ensures that the range is marked protected even if it's
> only defined through the devicetree and not only via commandline
> arguments.
>
> Reported-by: Mathieu Malaterre <mathieu.malaterre@xxxxxxxxx>
> Signed-off-by: Marcin Nowakowski <marcin.nowakowski@xxxxxxxx>
> Fixes: 73fbc1eba7ff ("MIPS: fix mem=X@Y commandline processing")
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.11
I'm guessing that should technically be v4.11+
> ---
> v2: Use updated email adress, add tag for stable.
> arch/mips/kernel/setup.c | 19 ++++++++++++++++---
> 1 file changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> index 702c678de116..f19d61224c71 100644
> --- a/arch/mips/kernel/setup.c
> +++ b/arch/mips/kernel/setup.c
> @@ -375,6 +375,7 @@ static void __init bootmem_init(void)
> unsigned long reserved_end;
> unsigned long mapstart = ~0UL;
> unsigned long bootmap_size;
> + phys_addr_t ramstart = ~0UL;
Although practically it might not matter, technically phys_addr_t may be
64-bits (CONFIG_PHYS_ADDR_T_64BIT) even on a 32-bit kernels, in which
case ~0UL may not be sufficiently large.
Maybe that should be ~(phys_addr_t)0, or perhaps (phys_addr_t)ULLONG_MAX
to match add_memory_region().
> bool bootmap_valid = false;
> int i;
>
> @@ -395,6 +396,21 @@ static void __init bootmem_init(void)
> max_low_pfn = 0;
>
> /*
> + * Reserve any memory between the start of RAM and PHYS_OFFSET
> + */
> + for (i = 0; i < boot_mem_map.nr_map; i++) {
> + if (boot_mem_map.map[i].type != BOOT_MEM_RAM)
> + continue;
> +
> + ramstart = min(ramstart, boot_mem_map.map[i].addr);
Is it worth incorporating this into the existing loop below ...
> + }
> +
> + if (ramstart > PHYS_OFFSET)
> + add_memory_region(PHYS_OFFSET, ramstart - PHYS_OFFSET,
> + BOOT_MEM_RESERVED);
... and this then placed below that loop?
Otherwise I can't find fault with this patch, though i'm not intimately
familiar with bootmem.
Cheers
James
> +
> +
> + /*
> * Find the highest page frame number we have available.
> */
> for (i = 0; i < boot_mem_map.nr_map; i++) {
> @@ -664,9 +680,6 @@ static int __init early_parse_mem(char *p)
>
> add_memory_region(start, size, BOOT_MEM_RAM);
>
> - if (start && start > PHYS_OFFSET)
> - add_memory_region(PHYS_OFFSET, start - PHYS_OFFSET,
> - BOOT_MEM_RESERVED);
> return 0;
> }
> early_param("mem", early_parse_mem);
> --
> 2.11.0
>
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