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| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2015-03-19 19:42:26 +0300 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2015-03-19 22:21:56 +0300 |
| commit | 06f75a1f6200042aa36ad40afb44dd72107b25d6 (patch) | |
| tree | 84f134705f009d74aba8637f25da3f887ea40c08 /arch/arm64/kernel/vmlinux.lds.S | |
| parent | 06e5801b8cb3fc057d88cb4dc03c0b64b2744cda (diff) | |
| download | linux-06f75a1f6200042aa36ad40afb44dd72107b25d6.tar.xz | |
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/arm64/kernel/vmlinux.lds.S')
| -rw-r--r-- | arch/arm64/kernel/vmlinux.lds.S | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 5d9d2dca530d..a2c29865c3fe 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -23,10 +23,14 @@ jiffies = jiffies_64; #define HYPERVISOR_TEXT \ /* \ - * Force the alignment to be compatible with \ - * the vectors requirements \ + * Align to 4 KB so that \ + * a) the HYP vector table is at its minimum \ + * alignment of 2048 bytes \ + * b) the HYP init code will not cross a page \ + * boundary if its size does not exceed \ + * 4 KB (see related ASSERT() below) \ */ \ - . = ALIGN(2048); \ + . = ALIGN(SZ_4K); \ VMLINUX_SYMBOL(__hyp_idmap_text_start) = .; \ *(.hyp.idmap.text) \ VMLINUX_SYMBOL(__hyp_idmap_text_end) = .; \ @@ -163,10 +167,11 @@ SECTIONS } /* - * 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. */ -ASSERT(((__hyp_idmap_text_start + PAGE_SIZE) > __hyp_idmap_text_end), - "HYP init code too big") +ASSERT(__hyp_idmap_text_end - (__hyp_idmap_text_start & ~(SZ_4K - 1)) <= SZ_4K, + "HYP init code too big or misaligned") /* * If padding is applied before .head.text, virt<->phys conversions will fail. |