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| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2015-06-01 13:40:33 +0200 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2015-06-02 18:44:51 +0200 |
| commit | 5dfe9d7d23c26d029415379630523f141a748c5b (patch) | |
| tree | 8ffc7d85d1f3bb5cd4021b115fe965aa290cb837 /arch/arm64/kernel/vmlinux.lds.S | |
| parent | arm64: use fixmap region for permanent FDT mapping (diff) | |
| download | linux-5dfe9d7d23c26d029415379630523f141a748c5b.tar.xz linux-5dfe9d7d23c26d029415379630523f141a748c5b.zip | |
arm64: reduce ID map to a single page
Commit ea8c2e112445 ("arm64: Extend the idmap to the whole kernel
image") changed the early page table code so that the entire kernel
Image is covered by the identity map. This allows functions that
need to enable or disable the MMU to reside anywhere in the kernel
Image.
However, this change has the unfortunate side effect that the Image
cannot cross a physical 512 MB alignment boundary anymore, since the
early page table code cannot deal with the Image crossing a /virtual/
512 MB alignment boundary.
So instead, reduce the ID map to a single page, that is populated by
the contents of the .idmap.text section. Only three functions reside
there at the moment: __enable_mmu(), cpu_resume_mmu() and cpu_reset().
If new code is introduced that needs to manipulate the MMU state, it
should be added to this section as well.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/vmlinux.lds.S')
| -rw-r--r-- | arch/arm64/kernel/vmlinux.lds.S | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index a2c29865c3fe..98073332e2d0 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -38,6 +38,12 @@ jiffies = jiffies_64; *(.hyp.text) \ VMLINUX_SYMBOL(__hyp_text_end) = .; +#define IDMAP_TEXT \ + . = ALIGN(SZ_4K); \ + VMLINUX_SYMBOL(__idmap_text_start) = .; \ + *(.idmap.text) \ + VMLINUX_SYMBOL(__idmap_text_end) = .; + /* * The size of the PE/COFF section that covers the kernel image, which * runs from stext to _edata, must be a round multiple of the PE/COFF @@ -95,6 +101,7 @@ SECTIONS SCHED_TEXT LOCK_TEXT HYPERVISOR_TEXT + IDMAP_TEXT *(.fixup) *(.gnu.warning) . = ALIGN(16); @@ -167,11 +174,13 @@ SECTIONS } /* - * The HYP init code can't be more than a page long, + * The HYP init code and ID map text can't be longer than a page each, * and should not cross a page boundary. */ ASSERT(__hyp_idmap_text_end - (__hyp_idmap_text_start & ~(SZ_4K - 1)) <= SZ_4K, "HYP init code too big or misaligned") +ASSERT(__idmap_text_end - (__idmap_text_start & ~(SZ_4K - 1)) <= SZ_4K, + "ID map text too big or misaligned") /* * If padding is applied before .head.text, virt<->phys conversions will fail. |