diff options
| author | Ard Biesheuvel | 2015-03-19 16:42:26 +0000 |
|---|---|---|
| committer | Will Deacon | 2015-03-19 19:21:56 +0000 |
| commit | 06f75a1f6200042aa36ad40afb44dd72107b25d6 (patch) | |
| tree | 84f134705f009d74aba8637f25da3f887ea40c08 /arch/arm/kernel | |
| parent | 06e5801b8cb3fc057d88cb4dc03c0b64b2744cda (diff) | |
ARM, arm64: kvm: get rid of the bounce page
The HYP init bounce page is a runtime construct that ensures that the
HYP init code does not cross a page boundary. However, this is something
we can do perfectly well at build time, by aligning the code appropriately.
For arm64, we just align to 4 KB, and enforce that the code size is less
than 4 KB, regardless of the chosen page size.
For ARM, the whole code is less than 256 bytes, so we tweak the linker
script to align at a power of 2 upper bound of the code size
Note that this also fixes a benign off-by-one error in the original bounce
page code, where a bounce page would be allocated unnecessarily if the code
was exactly 1 page in size.
On ARM, it also fixes an issue with very large kernels reported by Arnd
Bergmann, where stub sections with linker emitted veneers could erroneously
trigger the size/alignment ASSERT() in the linker script.
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm/kernel')
| -rw-r--r-- | arch/arm/kernel/vmlinux.lds.S | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S index b31aa73e8076..ba65f1217310 100644 --- a/arch/arm/kernel/vmlinux.lds.S +++ b/arch/arm/kernel/vmlinux.lds.S @@ -23,11 +23,20 @@ VMLINUX_SYMBOL(__idmap_text_start) = .; \ *(.idmap.text) \ VMLINUX_SYMBOL(__idmap_text_end) = .; \ - . = ALIGN(32); \ + . = ALIGN(1 << LOG2CEIL(__hyp_idmap_size)); \ VMLINUX_SYMBOL(__hyp_idmap_text_start) = .; \ *(.hyp.idmap.text) \ VMLINUX_SYMBOL(__hyp_idmap_text_end) = .; +/* + * If the HYP idmap .text section is populated, it needs to be positioned + * such that it will not cross a page boundary in the final output image. + * So align it to the section size rounded up to the next power of 2. + * If __hyp_idmap_size is undefined, the section will be empty so define + * it as 0 in that case. + */ +PROVIDE(__hyp_idmap_size = 0); + #ifdef CONFIG_HOTPLUG_CPU #define ARM_CPU_DISCARD(x) #define ARM_CPU_KEEP(x) x @@ -346,8 +355,11 @@ SECTIONS */ ASSERT((__proc_info_end - __proc_info_begin), "missing CPU support") ASSERT((__arch_info_end - __arch_info_begin), "no machine record defined") + /* - * The HYP init code can't be more than a page long. + * The HYP init code can't be more than a page long, + * and should not cross a page boundary. * The above comment applies as well. */ -ASSERT(((__hyp_idmap_text_end - __hyp_idmap_text_start) <= PAGE_SIZE), "HYP init code too big") +ASSERT((__hyp_idmap_text_start & ~PAGE_MASK) + __hyp_idmap_size <= PAGE_SIZE, + "HYP init code too big or misaligned") |