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SubjectRe: [PATCH v3] arm64: use generic free_initrd_mem()
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On 09/25/2019 10:39 AM, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> arm64 calls memblock_free() for the initrd area in its implementation of
> free_initrd_mem(), but this call has no actual effect that late in the boot
> process. By the time initrd is freed, all the reserved memory is managed by
> the page allocator and the memblock.reserved is unused, so the only purpose
> of the memblock_free() call is to keep track of initrd memory for debugging
> and accounting.
>
> Without the memblock_free() call the only difference between arm64 and the
> generic versions of free_initrd_mem() is the memory poisoning.
>
> Move memblock_free() call to the generic code, enable it there
> for the architectures that define ARCH_KEEP_MEMBLOCK and use the generic
> implementaion of free_initrd_mem() on arm64.

Small nit. s/implementaion/implementation.

>
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
>
> v3:
> * fix powerpc build
>
> v2:
> * add memblock_free() to the generic free_initrd_mem()
> * rebase on the current upstream
>
>
> arch/arm64/mm/init.c | 12 ------------
> init/initramfs.c | 5 +++++
> 2 files changed, 5 insertions(+), 12 deletions(-)
>
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 45c00a5..87a0e3b 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -580,18 +580,6 @@ void free_initmem(void)
> unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin));
> }
>
> -#ifdef CONFIG_BLK_DEV_INITRD
> -void __init free_initrd_mem(unsigned long start, unsigned long end)
> -{
> - unsigned long aligned_start, aligned_end;
> -
> - aligned_start = __virt_to_phys(start) & PAGE_MASK;
> - aligned_end = PAGE_ALIGN(__virt_to_phys(end));
> - memblock_free(aligned_start, aligned_end - aligned_start);
> - free_reserved_area((void *)start, (void *)end, 0, "initrd");
> -}
> -#endif
> -
> /*
> * Dump out memory limit information on panic.
> */
> diff --git a/init/initramfs.c b/init/initramfs.c
> index c47dad0..3d61e13 100644
> --- a/init/initramfs.c
> +++ b/init/initramfs.c
> @@ -10,6 +10,7 @@
> #include <linux/syscalls.h>
> #include <linux/utime.h>
> #include <linux/file.h>
> +#include <linux/memblock.h>
>
> static ssize_t __init xwrite(int fd, const char *p, size_t count)
> {
> @@ -531,6 +532,10 @@ void __weak free_initrd_mem(unsigned long start, unsigned long end)
> {
> free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
> "initrd");
> +
> +#ifdef CONFIG_ARCH_KEEP_MEMBLOCK

Should not the addresses here be aligned first before calling memblock_free() ?
Without alignment, it breaks present behavior on arm64 which was explicitly added
with 13776f9d40a0 ("arm64: mm: free the initrd reserved memblock in a aligned manner").
Or does initrd always gets allocated with page alignment on other architectures.

> + memblock_free(__pa(start), end - start);
> +#endif
> }
>
> #ifdef CONFIG_KEXEC_CORE
>

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