diff options
| author | Quentin Perret <qperret@google.com> | 2021-03-19 11:01:15 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2021-03-19 13:01:20 +0100 |
| commit | 380e18ade4a51334e8806160e6f0fdfaca0b4428 (patch) | |
| tree | fe82cfb30031b7030df54e9fc6360d14fcb32587 /arch/arm64/kernel | |
| parent | KVM: arm64: Factor memory allocation out of pgtable.c (diff) | |
| download | linux-380e18ade4a51334e8806160e6f0fdfaca0b4428.tar.xz linux-380e18ade4a51334e8806160e6f0fdfaca0b4428.zip | |
KVM: arm64: Introduce a BSS section for use at Hyp
Currently, the hyp code cannot make full use of a bss, as the kernel
section is mapped read-only.
While this mapping could simply be changed to read-write, it would
intermingle even more the hyp and kernel state than they currently are.
Instead, introduce a __hyp_bss section, that uses reserved pages, and
create the appropriate RW hyp mappings during KVM init.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-8-qperret@google.com
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/vmlinux.lds.S | 52 |
1 files changed, 34 insertions, 18 deletions
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 7eea7888bb02..e96173ce211b 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -5,24 +5,7 @@ * Written by Martin Mares <mj@atrey.karlin.mff.cuni.cz> */ -#define RO_EXCEPTION_TABLE_ALIGN 8 -#define RUNTIME_DISCARD_EXIT - -#include <asm-generic/vmlinux.lds.h> -#include <asm/cache.h> #include <asm/hyp_image.h> -#include <asm/kernel-pgtable.h> -#include <asm/memory.h> -#include <asm/page.h> - -#include "image.h" - -OUTPUT_ARCH(aarch64) -ENTRY(_text) - -jiffies = jiffies_64; - - #ifdef CONFIG_KVM #define HYPERVISOR_EXTABLE \ . = ALIGN(SZ_8); \ @@ -51,13 +34,43 @@ jiffies = jiffies_64; __hyp_reloc_end = .; \ } +#define BSS_FIRST_SECTIONS \ + __hyp_bss_start = .; \ + *(HYP_SECTION_NAME(.bss)) \ + . = ALIGN(PAGE_SIZE); \ + __hyp_bss_end = .; + +/* + * We require that __hyp_bss_start and __bss_start are aligned, and enforce it + * with an assertion. But the BSS_SECTION macro places an empty .sbss section + * between them, which can in some cases cause the linker to misalign them. To + * work around the issue, force a page alignment for __bss_start. + */ +#define SBSS_ALIGN PAGE_SIZE #else /* CONFIG_KVM */ #define HYPERVISOR_EXTABLE #define HYPERVISOR_DATA_SECTIONS #define HYPERVISOR_PERCPU_SECTION #define HYPERVISOR_RELOC_SECTION +#define SBSS_ALIGN 0 #endif +#define RO_EXCEPTION_TABLE_ALIGN 8 +#define RUNTIME_DISCARD_EXIT + +#include <asm-generic/vmlinux.lds.h> +#include <asm/cache.h> +#include <asm/kernel-pgtable.h> +#include <asm/memory.h> +#include <asm/page.h> + +#include "image.h" + +OUTPUT_ARCH(aarch64) +ENTRY(_text) + +jiffies = jiffies_64; + #define HYPERVISOR_TEXT \ /* \ * Align to 4 KB so that \ @@ -276,7 +289,7 @@ SECTIONS __pecoff_data_rawsize = ABSOLUTE(. - __initdata_begin); _edata = .; - BSS_SECTION(0, 0, 0) + BSS_SECTION(SBSS_ALIGN, 0, 0) . = ALIGN(PAGE_SIZE); init_pg_dir = .; @@ -324,6 +337,9 @@ ASSERT(__hibernate_exit_text_end - (__hibernate_exit_text_start & ~(SZ_4K - 1)) ASSERT((__entry_tramp_text_end - __entry_tramp_text_start) == PAGE_SIZE, "Entry trampoline text too big") #endif +#ifdef CONFIG_KVM +ASSERT(__hyp_bss_start == __bss_start, "HYP and Host BSS are misaligned") +#endif /* * If padding is applied before .head.text, virt<->phys conversions will fail. */ |