From: Josh Triplett <josh@joshtriplett.org>
To: linux-kernel@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Len Brown <lenb@kernel.org>,
Matt Fleming <matt.fleming@intel.com>,
Olof Johansson <olof@lixom.net>, Matthew Garrett <mjg@redhat.com>,
David Howells <dhowells@redhat.com>,
Rusty Russell <rusty@rustcorp.com.au>,
Jim Cromie <jim.cromie@gmail.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Pawel Moll <pawel.moll@arm.com>,
linux-acpi@vger.kernel.org
Subject: [PATCH 2/3] efi: Add a function to look up existing IO memory mappings
Date: Thu, 30 Aug 2012 14:28:45 -0700 [thread overview]
Message-ID: <5563b7d0ce3577f421e9622063a58aa4003ec917.1346361959.git.josh@joshtriplett.org> (raw)
In-Reply-To: <cover.1346361959.git.josh@joshtriplett.org>
The EFI initialization creates virtual mappings for EFI boot services
memory, so if a driver wants to access EFI boot services memory, it
cannot call ioremap itself; doing so will trip the WARN about mapping
RAM twice. Thus, a driver accessing EFI boot services memory must do so
via the existing mapping already created during EFI intiialization.
Since the EFI code already maintains a memory map for that memory, add a
function efi_lookup_mapped_addr to look up mappings in that memory map.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
---
arch/x86/platform/efi/efi.c | 28 ++++++++++++++++++++++++++++
include/linux/efi.h | 1 +
2 files changed, 29 insertions(+)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 8af329f..ae35cc8 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -777,6 +777,34 @@ static void __init runtime_code_page_mkexec(void)
}
/*
+ * We can't ioremap data in EFI boot services RAM, because we've already mapped
+ * it as RAM. So, look it up in the existing EFI memory map instead. Only
+ * callable after efi_enter_virtual_mode and before efi_free_boot_services.
+ */
+void __iomem *efi_lookup_mapped_addr(u64 phys_addr)
+{
+ void *p;
+ if (WARN_ON(!memmap.map))
+ return NULL;
+ for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
+ efi_memory_desc_t *md = p;
+ u64 size = md->num_pages << EFI_PAGE_SHIFT;
+ u64 end = md->phys_addr + size;
+ if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
+ md->type != EFI_BOOT_SERVICES_CODE &&
+ md->type != EFI_BOOT_SERVICES_DATA)
+ continue;
+ if (!md->virt_addr)
+ continue;
+ if (phys_addr >= md->phys_addr && phys_addr < end) {
+ phys_addr += md->virt_addr - md->phys_addr;
+ return (__force void __iomem *)phys_addr;
+ }
+ }
+ return NULL;
+}
+
+/*
* This function will switch the EFI runtime services to virtual mode.
* Essentially, look through the EFI memmap and map every region that
* has the runtime attribute bit set in its memory descriptor and update
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 00ec70f..0c11a58 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -496,6 +496,7 @@ extern void efi_map_pal_code (void);
extern void efi_memmap_walk (efi_freemem_callback_t callback, void *arg);
extern void efi_gettimeofday (struct timespec *ts);
extern void efi_enter_virtual_mode (void); /* switch EFI to virtual mode, if possible */
+extern void __iomem *efi_lookup_mapped_addr(u64 phys_addr);
extern void efi_free_boot_services(void);
extern u64 efi_get_iobase (void);
extern u32 efi_mem_type (unsigned long phys_addr);
--
1.7.10.4
next prev parent reply other threads:[~2012-08-30 21:28 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-30 21:28 [PATCH 0/3] Fix ACPI BGRT support for images located in EFI boot services memory Josh Triplett
2012-08-30 21:28 ` [PATCH 1/3] efi: Defer freeing boot services memory until after ACPI init Josh Triplett
2012-08-30 21:28 ` Josh Triplett [this message]
2012-08-30 21:28 ` [PATCH 3/3] efi: Fix the ACPI BGRT driver for images located in EFI boot services memory Josh Triplett
2012-09-04 14:27 ` [PATCH 0/3] Fix ACPI BGRT support " Matt Fleming
2012-09-04 17:59 ` Josh Triplett
2012-09-04 18:10 ` H. Peter Anvin
2012-09-04 19:45 ` Josh Triplett
2012-09-04 20:24 ` H. Peter Anvin
2012-09-04 20:29 ` Josh Triplett
2012-09-04 20:11 ` Matt Fleming
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