powerpc/64: Fix the definition of the fixmap area

At the time being, the fixmap area is defined at the top of
the address space or just below KASAN.

This definition is not valid for PPC64.

For PPC64, use the top of the I/O space.

Because of circular dependencies, it is not possible to include
asm/fixmap.h in asm/book3s/64/pgtable.h , so define a fixed size
AREA at the top of the I/O space for fixmap and ensure during
build that the size is big enough.

Fixes: 265c3491c4bc ("powerpc: Add support for GENERIC_EARLY_IOREMAP")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0d51620eacf036d683d1a3c41328f69adb601dc0.1618925560.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 0c89977ec10bf01a8038f634ecf30bfe900251ae..a666d561b44d2825e079dd7efa7f37b7b9f4f136 100644 (file)
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -7,6 +7,7 @@
 #ifndef __ASSEMBLY__
 #include <linux/mmdebug.h>
 #include <linux/bug.h>
+#include <linux/sizes.h>
 #endif
 
 /*
@@ -324,7 +325,8 @@ extern unsigned long pci_io_base;
 #define  PHB_IO_END    (KERN_IO_START + FULL_IO_SIZE)
 #define IOREMAP_BASE   (PHB_IO_END)
 #define IOREMAP_START  (ioremap_bot)
-#define IOREMAP_END    (KERN_IO_END)
+#define IOREMAP_END    (KERN_IO_END - FIXADDR_SIZE)
+#define FIXADDR_SIZE   SZ_32M
 
 /* Advertise special mapping type for AGP */
 #define HAVE_PAGE_AGP

diff --git a/arch/powerpc/include/asm/fixmap.h b/arch/powerpc/include/asm/fixmap.h
index 8d03c16a3663548cf7fe9c80b629761803e89192..947b5b9c44241124ef3c00816041127d821a05e8 100644 (file)
--- a/arch/powerpc/include/asm/fixmap.h
+++ b/arch/powerpc/include/asm/fixmap.h
@@ -23,12 +23,17 @@
 #include <asm/kmap_size.h>
 #endif
 
+#ifdef CONFIG_PPC64
+#define FIXADDR_TOP    (IOREMAP_END + FIXADDR_SIZE)
+#else
+#define FIXADDR_SIZE   0
 #ifdef CONFIG_KASAN
 #include <asm/kasan.h>
 #define FIXADDR_TOP    (KASAN_SHADOW_START - PAGE_SIZE)
 #else
 #define FIXADDR_TOP    ((unsigned long)(-PAGE_SIZE))
 #endif
+#endif
 
 /*
  * Here we define all the compile-time 'special' virtual
@@ -50,6 +55,7 @@
  */
 enum fixed_addresses {
        FIX_HOLE,
+#ifdef CONFIG_PPC32
        /* reserve the top 128K for early debugging purposes */
        FIX_EARLY_DEBUG_TOP = FIX_HOLE,
        FIX_EARLY_DEBUG_BASE = FIX_EARLY_DEBUG_TOP+(ALIGN(SZ_128K, PAGE_SIZE)/PAGE_SIZE)-1,
@@ -72,6 +78,7 @@ enum fixed_addresses {
                       FIX_IMMR_SIZE,
 #endif
        /* FIX_PCIE_MCFG, */
+#endif /* CONFIG_PPC32 */
        __end_of_permanent_fixed_addresses,
 
 #define NR_FIX_BTMAPS          (SZ_256K / PAGE_SIZE)
@@ -98,6 +105,8 @@ enum fixed_addresses {
 static inline void __set_fixmap(enum fixed_addresses idx,
                                phys_addr_t phys, pgprot_t flags)
 {
+       BUILD_BUG_ON(IS_ENABLED(CONFIG_PPC64) && __FIXADDR_SIZE > FIXADDR_SIZE);
+
        if (__builtin_constant_p(idx))
                BUILD_BUG_ON(idx >= __end_of_fixed_addresses);
        else if (WARN_ON(idx >= __end_of_fixed_addresses))

diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h
index 6cb8aa35719176a297218f94e6ef089351e5bd77..57cd3892bfe05237231e929fb1284612d9d13cbe 100644 (file)
--- a/arch/powerpc/include/asm/nohash/64/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
@@ -6,6 +6,8 @@
  * the ppc64 non-hashed page table.
  */
 
+#include <linux/sizes.h>
+
 #include <asm/nohash/64/pgtable-4k.h>
 #include <asm/barrier.h>
 #include <asm/asm-const.h>
@@ -54,7 +56,8 @@
 #define  PHB_IO_END    (KERN_IO_START + FULL_IO_SIZE)
 #define IOREMAP_BASE   (PHB_IO_END)
 #define IOREMAP_START  (ioremap_bot)
-#define IOREMAP_END    (KERN_VIRT_START + KERN_VIRT_SIZE)
+#define IOREMAP_END    (KERN_VIRT_START + KERN_VIRT_SIZE - FIXADDR_SIZE)
+#define FIXADDR_SIZE   SZ_32M
 
 
 /*