The reason why mapping idt_table to fixmap area should also be applied to debug_idt_table and trace_idt_table. This patch does same thing for all IDTs.
Signed-off-by: Wang Nan <wangn...@huawei.com> --- I believe trace_idt_table and debug_idt_table should be symmetrical with idt_table. However, Like my previous patch 'x86, traps: install gates using IST after cpu_init()', I'm not sure whether this is a practical fix. --- arch/x86/include/asm/fixmap.h | 6 ++++++ arch/x86/kernel/tracepoint.c | 2 +- arch/x86/kernel/traps.c | 13 +++++++++++-- arch/x86/xen/mmu.c | 6 ++++++ 4 files changed, 24 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index f80d700..79550f4 100644 --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -90,6 +90,12 @@ enum fixed_addresses { FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS - 1, #endif FIX_RO_IDT, /* Virtual mapping for read-only IDT */ +#ifdef CONFIG_X86_64 + FIX_RO_DEBUG_IDT, /* Virtual mapping for read-only debug_idt_table */ +#endif +#ifdef CONFIG_TRACING + FIX_RO_TRACE_IDT, /* Virtual mapping for read-only trace_idt_table */ +#endif #ifdef CONFIG_X86_32 FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */ FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1, diff --git a/arch/x86/kernel/tracepoint.c b/arch/x86/kernel/tracepoint.c index 1c113db..296e130 100644 --- a/arch/x86/kernel/tracepoint.c +++ b/arch/x86/kernel/tracepoint.c @@ -12,7 +12,7 @@ atomic_t trace_idt_ctr = ATOMIC_INIT(0); struct desc_ptr trace_idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) trace_idt_table }; -/* No need to be aligned, but done to keep all IDTs defined the same way. */ +/* Must be page-aligned because the real IDT is used in a fixmap. */ gate_desc trace_idt_table[NR_VECTORS] __page_aligned_bss; static int trace_irq_vector_refcount; diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index cf7898e..6d88c37 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -67,7 +67,7 @@ #include <asm/pgalloc.h> #include <asm/proto.h> -/* No need to be aligned, but done to keep all IDTs defined the same way. */ +/* Must be page-aligned because the real IDT is used in a fixmap. */ gate_desc debug_idt_table[NR_VECTORS] __page_aligned_bss; #else #include <asm/processor-flags.h> @@ -998,9 +998,18 @@ void __init trap_init(void) * Set the IDT descriptor to a fixed read-only location, so that the * "sidt" instruction will not leak the location of the kernel, and * to defend the IDT against arbitrary memory write vulnerabilities. - * It will be reloaded in cpu_init() */ + * It will be reloaded in cpu_init() + */ __set_fixmap(FIX_RO_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO); idt_descr.address = fix_to_virt(FIX_RO_IDT); +#ifdef CONFIG_X86_64 + __set_fixmap(FIX_RO_DEBUG_IDT, __pa_symbol(debug_idt_table), PAGE_KERNEL_RO); + debug_idt_descr.address = fix_to_virt(FIX_RO_DEBUG_IDT); +#endif +#ifdef CONFIG_TRACING + __set_fixmap(FIX_RO_TRACE_IDT, __pa_symbol(trace_idt_table), PAGE_KERNEL_RO); + trace_idt_descr.address = fix_to_virt(FIX_RO_TRACE_IDT); +#endif /* * Should be a barrier for any external CPU state: diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index adca9e2..1fd4a4c 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -1984,6 +1984,12 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot) switch (idx) { case FIX_BTMAP_END ... FIX_BTMAP_BEGIN: case FIX_RO_IDT: +#ifdef CONFIG_X86_64 + case FIX_RO_DEBUG_IDT: +#endif +#ifdef CONFIG_TRACING + case FIX_RO_TRACE_IDT: +#endif #ifdef CONFIG_X86_32 case FIX_WP_TEST: # ifdef CONFIG_HIGHMEM -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/