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Date: Wed, 18 May 2016 14:11:41 -0500
From: Alex Thorlton <athorlton@....com>
To: linux-kernel@...r.kernel.org
Cc: Alex Thorlton <athorlton@....com>,
Matt Fleming <matt@...eblueprint.co.uk>,
Borislav Petkov <bp@...e.de>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>, Mike Travis <travis@....com>,
Russ Anderson <rja@....com>,
Dimitri Sivanich <sivanich@....com>, x86@...nel.org,
linux-efi@...r.kernel.org
Subject: [PATCH 3/3] Update efi_thunk to use efi_call_virt_generic
Now that we have efi_call_virt_generic, we no longer need to have an
entirely separate efi_thunk macro to handle the CONFIG_EFI_MIXED
scenario, where the function pointers cannot be read directly out of
efi.systab->runtime.
This commit creates a new set of arch_efi_call_virt* macros to mimic the
behavior of the old efi_thunk macro. In the end, the code should be the
same, functionally, but we'll have eliminated a good chunk of code
duplication by splitting the efi_thunk macro up into the appropriate
arch_efi_call_virt bits and then just calling efi_call_virt_generic,
instead of efi_thunk. I do go ahead and create a new efi_thunk macro in
arch/x86/platform/efi/efi_64.c, but this is mainly to keep the existing
code clean.
One thing to note here, is that this is not and absolutely *perfect* use
of the efi_call_virt_generic macro, in that it still has the
efi.systab->runtime pointer hard-coded into runtime_service32. For now,
I think this should be fine, as the only users of the function already
assumed that this was where their function pointer would come from. If
another CONFIG_EFI_MIXED user comes along and needs to use
efi_call_virt_generic, then we will need to re-think things a bit.
Signed-off-by: Alex Thorlton <athorlton@....com>
Cc: Matt Fleming <matt@...eblueprint.co.uk>
Cc: Borislav Petkov <bp@...e.de>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Mike Travis <travis@....com>
Cc: Russ Anderson <rja@....com>
Cc: Dimitri Sivanich <sivanich@....com>
Cc: x86@...nel.org
Cc: linux-efi@...r.kernel.org
---
arch/x86/include/asm/efi.h | 47 ++++++++++++++++++++++++++++++++++++++++
arch/x86/platform/efi/efi_64.c | 49 ++++++++++--------------------------------
2 files changed, 58 insertions(+), 38 deletions(-)
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index f310f0b..6643f9b 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -68,6 +68,52 @@ struct efi_scratch {
u64 phys_stack;
} __packed;
+#ifdef CONFIG_EFI_MIXED
+extern efi_status_t efi64_thunk(u32, ...);
+
+#define runtime_service32(func) \
+({ \
+ u32 table = (u32)(unsigned long)efi.systab; \
+ u32 *rt, *___f; \
+ \
+ rt = (u32 *)(table + offsetof(efi_system_table_32_t, runtime)); \
+ ___f = (u32 *)(*rt + offsetof(efi_runtime_services_32_t, func)); \
+ *___f; \
+})
+
+/*
+ * Switch to the EFI page tables early so that we can access the 1:1
+ * runtime services mappings which are not mapped in any other page
+ * tables. This function must be called before runtime_service32().
+ *
+ * Also, disable interrupts because the IDT points to 64-bit handlers,
+ * which aren't going to function correctly when we switch to 32-bit.
+ */
+#define arch_efi_call_virt_setup() \
+({ \
+ efi_sync_low_kernel_mappings(); \
+ local_irq_save(flags); \
+ \
+ efi_scratch.prev_cr3 = read_cr3(); \
+ write_cr3((unsigned long)efi_scratch.efi_pgt); \
+ __flush_tlb_all(); \
+})
+
+#define arch_efi_call_virt(p, f, ...) \
+({ \
+ u32 func = runtime_service32(f); \
+ efi64_thunk(func, __VA_ARGS__); \
+})
+
+#define arch_efi_call_virt_teardown() \
+({ \
+ write_cr3(efi_scratch.prev_cr3); \
+ __flush_tlb_all(); \
+ local_irq_restore(flags); \
+})
+
+#else /* !CONFIG_EFI_MIXED */
+
#define arch_efi_call_virt_setup() \
({ \
efi_sync_low_kernel_mappings(); \
@@ -94,6 +140,7 @@ struct efi_scratch {
__kernel_fpu_end(); \
preempt_enable(); \
})
+#endif
extern void __iomem *__init efi_ioremap(unsigned long addr, unsigned long size,
u32 type, u64 attribute);
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index 6e7242b..747bbc3 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -443,48 +443,21 @@ void __init efi_dump_pagetable(void)
}
#ifdef CONFIG_EFI_MIXED
-extern efi_status_t efi64_thunk(u32, ...);
-
-#define runtime_service32(func) \
-({ \
- u32 table = (u32)(unsigned long)efi.systab; \
- u32 *rt, *___f; \
- \
- rt = (u32 *)(table + offsetof(efi_system_table_32_t, runtime)); \
- ___f = (u32 *)(*rt + offsetof(efi_runtime_services_32_t, func)); \
- *___f; \
-})
/*
- * Switch to the EFI page tables early so that we can access the 1:1
- * runtime services mappings which are not mapped in any other page
- * tables. This function must be called before runtime_service32().
+ * Note that we pass in NULL here instead of the systab/function name combo
+ * that usually gets us what we need. This is because the EFI_MIXED code
+ * still assumes that all EFI callback function pointers will be in
+ * efi.systab->runtime. Currently there are no users in the EFI_MIXED code
+ * that require efi_thunk to behave otherwise.
*
- * Also, disable interrupts because the IDT points to 64-bit handlers,
- * which aren't going to function correctly when we switch to 32-bit.
+ * If EFI_MIXED users want to call runtime functions that *don't* live in
+ * efi.systab->runtime, runtime_service32 and some of the related macros
+ * will need to be updated to handle this. Not a major headache, but
+ * something to keep in mind.
*/
-#define efi_thunk(f, ...) \
-({ \
- efi_status_t __s; \
- unsigned long flags; \
- u32 func; \
- \
- efi_sync_low_kernel_mappings(); \
- local_irq_save(flags); \
- \
- efi_scratch.prev_cr3 = read_cr3(); \
- write_cr3((unsigned long)efi_scratch.efi_pgt); \
- __flush_tlb_all(); \
- \
- func = runtime_service32(f); \
- __s = efi64_thunk(func, __VA_ARGS__); \
- \
- write_cr3(efi_scratch.prev_cr3); \
- __flush_tlb_all(); \
- local_irq_restore(flags); \
- \
- __s; \
-})
+#define efi_thunk(f, args...) \
+ efi_call_virt_generic(NULL, f, args)
efi_status_t efi_thunk_set_virtual_address_map(
void *phys_set_virtual_address_map,
--
1.8.5.6
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