From: Mark Salter msalter@redhat.com
When booting an arm64 kernel w/initrd using UEFI/grub, use of mem= will likely cut off part or all of the initrd. This leaves it outside the kernel linear map which leads to failure when unpacking. The x86 code has a similar need to relocate an initrd outside of mapped memory in some cases.
The current x86 code uses early_memremap() to copy the original initrd from unmapped to mapped RAM. This patchset creates a generic copy_from_early_mem() utility based on that x86 code and has arm64 and x86 share it in their respective initrd relocation code.
This patch (of 3):
In some early boot circumstances, it may be necessary to copy from RAM outside the kernel linear mapping to mapped RAM. The need to relocate an initrd is one example in the x86 code. This patch creates a helper function based on current x86 code.
Signed-off-by: Mark Salter msalter@redhat.com Cc: Catalin Marinas catalin.marinas@arm.com Cc: Will Deacon will.deacon@arm.com Cc: Arnd Bergmann arnd@arndb.de Cc: Ard Biesheuvel ard.biesheuvel@linaro.org Cc: Mark Rutland mark.rutland@arm.com Cc: Russell King rmk@arm.linux.org.uk Cc: Ingo Molnar mingo@elte.hu Cc: Thomas Gleixner tglx@linutronix.de Cc: "H. Peter Anvin" hpa@zytor.com Cc: Yinghai Lu yinghai@kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org (cherry picked from commit 6b0f68e32ea8749ff7d4a66cd5761e915e48e59d) Signed-off-by: Alex Shi alex.shi@linaro.org --- include/asm-generic/early_ioremap.h | 6 ++++++ mm/early_ioremap.c | 22 ++++++++++++++++++++++ 2 files changed, 28 insertions(+)
diff --git a/include/asm-generic/early_ioremap.h b/include/asm-generic/early_ioremap.h index a5de55c..e539f27 100644 --- a/include/asm-generic/early_ioremap.h +++ b/include/asm-generic/early_ioremap.h @@ -33,6 +33,12 @@ extern void early_ioremap_setup(void); */ extern void early_ioremap_reset(void);
+/* + * Early copy from unmapped memory to kernel mapped memory. + */ +extern void copy_from_early_mem(void *dest, phys_addr_t src, + unsigned long size); + #else static inline void early_ioremap_init(void) { } static inline void early_ioremap_setup(void) { } diff --git a/mm/early_ioremap.c b/mm/early_ioremap.c index e10ccd2..a0baeb4 100644 --- a/mm/early_ioremap.c +++ b/mm/early_ioremap.c @@ -217,6 +217,28 @@ early_memremap(resource_size_t phys_addr, unsigned long size) return (__force void *)__early_ioremap(phys_addr, size, FIXMAP_PAGE_NORMAL); } + +#define MAX_MAP_CHUNK (NR_FIX_BTMAPS << PAGE_SHIFT) + +void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size) +{ + unsigned long slop, clen; + char *p; + + while (size) { + slop = src & ~PAGE_MASK; + clen = size; + if (clen > MAX_MAP_CHUNK - slop) + clen = MAX_MAP_CHUNK - slop; + p = early_memremap(src & PAGE_MASK, clen + slop); + memcpy(dest, p + slop, clen); + early_memunmap(p, clen + slop); + dest += clen; + src += clen; + size -= clen; + } +} + #else /* CONFIG_MMU */
void __init __iomem *