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    Subject[stable:PATCH v4.9.309 33/43] arm64: entry: Allow the trampoline text to occupy multiple pages
    Date
    commit a9c406e6462ff14956d690de7bbe5131a5677dc9 upstream.

    Adding a second set of vectors to .entry.tramp.text will make it
    larger than a single 4K page.

    Allow the trampoline text to occupy up to three pages by adding two
    more fixmap slots. Previous changes to tramp_valias allowed it to reach
    beyond a single page.

    Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
    Signed-off-by: James Morse <james.morse@arm.com>
    ---
    arch/arm64/include/asm/fixmap.h | 6 ++++--
    arch/arm64/include/asm/sections.h | 6 ++++++
    arch/arm64/kernel/entry.S | 2 +-
    arch/arm64/kernel/vmlinux.lds.S | 2 +-
    arch/arm64/mm/mmu.c | 11 ++++++++---
    5 files changed, 20 insertions(+), 7 deletions(-)

    diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
    index feee38303afe..4ffe0d698fa7 100644
    --- a/arch/arm64/include/asm/fixmap.h
    +++ b/arch/arm64/include/asm/fixmap.h
    @@ -53,9 +53,11 @@ enum fixed_addresses {
    FIX_TEXT_POKE0,

    #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
    - FIX_ENTRY_TRAMP_TEXT,
    + FIX_ENTRY_TRAMP_TEXT3,
    + FIX_ENTRY_TRAMP_TEXT2,
    + FIX_ENTRY_TRAMP_TEXT1,
    FIX_ENTRY_TRAMP_DATA,
    -#define TRAMP_VALIAS (__fix_to_virt(FIX_ENTRY_TRAMP_TEXT))
    +#define TRAMP_VALIAS (__fix_to_virt(FIX_ENTRY_TRAMP_TEXT1))
    #endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */
    __end_of_permanent_fixed_addresses,

    diff --git a/arch/arm64/include/asm/sections.h b/arch/arm64/include/asm/sections.h
    index 4e7e7067afdb..09ebd37d5aa3 100644
    --- a/arch/arm64/include/asm/sections.h
    +++ b/arch/arm64/include/asm/sections.h
    @@ -26,5 +26,11 @@ extern char __hyp_text_start[], __hyp_text_end[];
    extern char __idmap_text_start[], __idmap_text_end[];
    extern char __irqentry_text_start[], __irqentry_text_end[];
    extern char __mmuoff_data_start[], __mmuoff_data_end[];
    +extern char __entry_tramp_text_start[], __entry_tramp_text_end[];
    +
    +static inline size_t entry_tramp_text_size(void)
    +{
    + return __entry_tramp_text_end - __entry_tramp_text_start;
    +}

    #endif /* __ASM_SECTIONS_H */
    diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
    index 6e1d02d87d45..b9a757216a80 100644
    --- a/arch/arm64/kernel/entry.S
    +++ b/arch/arm64/kernel/entry.S
    @@ -917,7 +917,7 @@ __ni_sys_trace:
    .endm

    .macro tramp_data_page dst
    - adr \dst, .entry.tramp.text
    + adr_l \dst, .entry.tramp.text
    sub \dst, \dst, PAGE_SIZE
    .endm

    diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
    index fa3ffad50a61..17fc1671b990 100644
    --- a/arch/arm64/kernel/vmlinux.lds.S
    +++ b/arch/arm64/kernel/vmlinux.lds.S
    @@ -261,7 +261,7 @@ ASSERT(__hibernate_exit_text_end - (__hibernate_exit_text_start & ~(SZ_4K - 1))
    <= SZ_4K, "Hibernate exit text too big or misaligned")
    #endif
    #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
    -ASSERT((__entry_tramp_text_end - __entry_tramp_text_start) == PAGE_SIZE,
    +ASSERT((__entry_tramp_text_end - __entry_tramp_text_start) <= 3*PAGE_SIZE,
    "Entry trampoline text too big")
    #endif
    /*
    diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
    index 60be5bc0984a..36bd50091c4b 100644
    --- a/arch/arm64/mm/mmu.c
    +++ b/arch/arm64/mm/mmu.c
    @@ -438,6 +438,7 @@ static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end,
    #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
    static int __init map_entry_trampoline(void)
    {
    + int i;
    extern char __entry_tramp_text_start[];

    pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
    @@ -448,11 +449,15 @@ static int __init map_entry_trampoline(void)

    /* Map only the text into the trampoline page table */
    memset(tramp_pg_dir, 0, PGD_SIZE);
    - __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE,
    - prot, pgd_pgtable_alloc, 0);
    + __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS,
    + entry_tramp_text_size(), prot, pgd_pgtable_alloc,
    + 0);

    /* Map both the text and data into the kernel page table */
    - __set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot);
    + for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++)
    + __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i,
    + pa_start + i * PAGE_SIZE, prot);
    +
    if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
    extern char __entry_tramp_data_start[];

    --
    2.30.2
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