On Mon, Feb 25, 2019 at 03:59:56PM +0800, Pingfan Liu wrote:
>crashkernel=x@y option may fail to reserve the required memory region if
>KASLR puts kernel into the region. To avoid this uncertainty, making KASLR
>skip the required region.
>
>Signed-off-by: Pingfan Liu <[email protected]>
>Cc: Thomas Gleixner <[email protected]>
>Cc: Ingo Molnar <[email protected]>
>Cc: Borislav Petkov <[email protected]>
>Cc: "H. Peter Anvin" <[email protected]>
>Cc: Baoquan He <[email protected]>
>Cc: Will Deacon <[email protected]>
>Cc: Nicolas Pitre <[email protected]>
>Cc: Pingfan Liu <[email protected]>
>Cc: Chao Fan <[email protected]>
>Cc: "Kirill A. Shutemov" <[email protected]>
>Cc: Ard Biesheuvel <[email protected]>
>Cc: [email protected]
>---
> arch/x86/boot/compressed/kaslr.c | 26 +++++++++++++++++++++++++-
> 1 file changed, 25 insertions(+), 1 deletion(-)
>
Hi Pingfan,
Some not important comments:
>diff --git a/arch/x86/boot/compressed/kaslr.c
>b/arch/x86/boot/compressed/kaslr.c
>index 9ed9709..728bc4b 100644
>--- a/arch/x86/boot/compressed/kaslr.c
>+++ b/arch/x86/boot/compressed/kaslr.c
>@@ -109,6 +109,7 @@ enum mem_avoid_index {
> MEM_AVOID_BOOTPARAMS,
> MEM_AVOID_MEMMAP_BEGIN,
> MEM_AVOID_MEMMAP_END = MEM_AVOID_MEMMAP_BEGIN + MAX_MEMMAP_REGIONS - 1,
>+ MEM_AVOID_CRASHKERNEL,
> MEM_AVOID_MAX,
> };
>
>@@ -240,6 +241,27 @@ static void parse_gb_huge_pages(char *param, char *val)
> }
> }
>
>+/* parse crashkernel=x@y option */
>+static int mem_avoid_crashkernel_simple(char *option)
>+{
>+ char *cur = option;
>+ unsigned long long crash_size, crash_base;
Change the position of two lines above.
>+
>+ crash_size = memparse(option, &cur);
>+ if (option == cur)
>+ return -EINVAL;
>+
>+ if (*cur == '@') {
>+ option = cur + 1;
>+ crash_base = memparse(option, &cur);
>+ if (option == cur)
>+ return -EINVAL;
>+ mem_avoid[MEM_AVOID_CRASHKERNEL].start = crash_base;
>+ mem_avoid[MEM_AVOID_CRASHKERNEL].size = crash_size;
>+ }
>+
>+ return 0;
You just call this function and don't use its return value.
So why not change it as void type.
>+}
>
> static void handle_mem_options(void)
If you want to change this function, I think you could change the
function name and the comment:
/* Mark the memmap regions we need to avoid */
handle_mem_options();
> {
>@@ -250,7 +272,7 @@ static void handle_mem_options(void)
> u64 mem_size;
>
> if (!strstr(args, "memmap=") && !strstr(args, "mem=") &&
>- !strstr(args, "hugepages"))
>+ !strstr(args, "hugepages") && !strstr(args, "crashkernel="))
> return;
>
> tmp_cmdline = malloc(len + 1);
>@@ -286,6 +308,8 @@ static void handle_mem_options(void)
> goto out;
>
> mem_limit = mem_size;
>+ } else if (strstr(param, "crashkernel")) {
>+ mem_avoid_crashkernel_simple(val);
I am wondering why you call this function mem_avoid_crashkernel_*simple*().
Thanks,
Chao Fan
> }
> }
>
>--
>2.7.4
>
>
>
