x86: replace hard coded reservations in 64-bit early boot code with dynamic table

On x86-64 there are several memory allocations before bootmem. To avoid
them stomping on each other they used to be all hard coded in bad_area().
Replace this with an array that is filled as needed.

This cleans up the code considerably and allows to expand its use.

Cc: peterz@infradead.org
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

7 files changed, 110 insertions, 112 deletions

diff --git a/arch/x86/kernel/e820_64.c b/arch/x86/kernel/e820_64.c
index 07cfaae7ab07..f8b7bebb4344 100644
--- a/arch/x86/kernel/e820_64.c
+++ b/arch/x86/kernel/e820_64.c
@@ -47,56 +47,65 @@ unsigned long end_pfn_map;
  */
 static unsigned long __initdata end_user_pfn = MAXMEM>>PAGE_SHIFT;
 
-/* Check for some hardcoded bad areas that early boot is not allowed to touch */
-static inline int bad_addr(unsigned long *addrp, unsigned long size)
-{
-        unsigned long addr = *addrp, last = addr + size;
+/*
+ * Early reserved memory areas.
+ */
+#define MAX_EARLY_RES 20
+
+struct early_res {
+        unsigned long start, end;
+};
+static struct early_res early_res[MAX_EARLY_RES] __initdata = {
+        { 0, PAGE_SIZE },                       /* BIOS data page */
+#ifdef CONFIG_SMP
+        { SMP_TRAMPOLINE_BASE, SMP_TRAMPOLINE_BASE + 2*PAGE_SIZE },
+#endif
+        {}
+};
 
-        /* various gunk below that needed for SMP startup */
-        if (addr < 0x8000) {
-                *addrp = PAGE_ALIGN(0x8000);
-                return 1;
+void __init reserve_early(unsigned long start, unsigned long end)
+{
+        int i;
+        struct early_res *r;
+        for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
+                r = &early_res[i];
+                if (end > r->start && start < r->end)
+                        panic("Duplicated early reservation %lx-%lx\n",
+                              start, end);
         }
+        if (i >= MAX_EARLY_RES)
+                panic("Too many early reservations");
+        r = &early_res[i];
+        r->start = start;
+        r->end = end;
+}
 
-        /* direct mapping tables of the kernel */
-        if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) {
-                *addrp = PAGE_ALIGN(table_end << PAGE_SHIFT);
-                return 1;
+void __init early_res_to_bootmem(void)
+{
+        int i;
+        for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
+                struct early_res *r = &early_res[i];
+                reserve_bootmem_generic(r->start, r->end - r->start);
         }
+}
 
-        /* initrd */
-#ifdef CONFIG_BLK_DEV_INITRD
-        if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
-                unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
-                unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
-                unsigned long ramdisk_end   = ramdisk_image+ramdisk_size;
-
-                if (last >= ramdisk_image && addr < ramdisk_end) {
-                        *addrp = PAGE_ALIGN(ramdisk_end);
-                        return 1;
+/* Check for already reserved areas */
+static inline int bad_addr(unsigned long *addrp, unsigned long size)
+{
+        int i;
+        unsigned long addr = *addrp, last;
+        int changed = 0;
+again:
+        last = addr + size;
+        for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
+                struct early_res *r = &early_res[i];
+                if (last >= r->start && addr < r->end) {
+                        *addrp = addr = r->end;
+                        changed = 1;
+                        goto again;
                 }
         }
-#endif
-        /* kernel code */
-        if (last >= __pa_symbol(&_text) && addr < __pa_symbol(&_end)) {
-                *addrp = PAGE_ALIGN(__pa_symbol(&_end));
-                return 1;
-        }
-
-        if (last >= ebda_addr && addr < ebda_addr + ebda_size) {
-                *addrp = PAGE_ALIGN(ebda_addr + ebda_size);
-                return 1;
-        }
-
-#ifdef CONFIG_NUMA
-        /* NUMA memory to node map */
-        if (last >= nodemap_addr && addr < nodemap_addr + nodemap_size) {
-                *addrp = nodemap_addr + nodemap_size;
-                return 1;
-        }
-#endif
-        /* XXX ramdisk image here? */
-        return 0;
+        return changed;
 }
 
 /*
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 87e031d4abf1..58438bafedca 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -21,6 +21,7 @@
 #include <asm/tlbflush.h>
 #include <asm/sections.h>
 #include <asm/kdebug.h>
+#include <asm/e820.h>
 
 static void __init zap_identity_mappings(void)
 {
@@ -48,6 +49,35 @@ static void __init copy_bootdata(char *real_mode_data)
         }
 }
 
+#define EBDA_ADDR_POINTER 0x40E
+
+static __init void reserve_ebda(void)
+{
+        unsigned ebda_addr, ebda_size;
+
+        /*
+         * there is a real-mode segmented pointer pointing to the
+         * 4K EBDA area at 0x40E
+         */
+        ebda_addr = *(unsigned short *)__va(EBDA_ADDR_POINTER);
+        ebda_addr <<= 4;
+
+        if (!ebda_addr)
+                return;
+
+        ebda_size = *(unsigned short *)__va(ebda_addr);
+
+        /* Round EBDA up to pages */
+        if (ebda_size == 0)
+                ebda_size = 1;
+        ebda_size <<= 10;
+        ebda_size = round_up(ebda_size + (ebda_addr & ~PAGE_MASK), PAGE_SIZE);
+        if (ebda_size > 64*1024)
+                ebda_size = 64*1024;
+
+        reserve_early(ebda_addr, ebda_addr + ebda_size);
+}
+
 void __init x86_64_start_kernel(char * real_mode_data)
 {
         int i;
@@ -75,5 +105,23 @@ void __init x86_64_start_kernel(char * real_mode_data)
         pda_init(0);
         copy_bootdata(__va(real_mode_data));
 
+        reserve_early(__pa_symbol(&_text), __pa_symbol(&_end));
+
+        /* Reserve INITRD */
+        if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
+                unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
+                unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
+                unsigned long ramdisk_end   = ramdisk_image + ramdisk_size;
+                reserve_early(ramdisk_image, ramdisk_end);
+        }
+
+        reserve_ebda();
+
+        /*
+         * At this point everything still needed from the boot loader
+         * or BIOS or kernel text should be early reserved or marked not
+         * RAM in e820. All other memory is free game.
+         */
+
         start_kernel();
 }
diff --git a/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c
index 4a3f00b49236..6cbd15625dce 100644
--- a/arch/x86/kernel/setup_64.c
+++ b/arch/x86/kernel/setup_64.c
@@ -245,41 +245,6 @@ static inline void __init reserve_crashkernel(void)
 {}
 #endif
 
-#define EBDA_ADDR_POINTER 0x40E
-
-unsigned __initdata ebda_addr;
-unsigned __initdata ebda_size;
-
-static void __init discover_ebda(void)
-{
-        /*
-         * there is a real-mode segmented pointer pointing to the
-         * 4K EBDA area at 0x40E
-         */
-        ebda_addr = *(unsigned short *)__va(EBDA_ADDR_POINTER);
-        /*
-         * There can be some situations, like paravirtualized guests,
-         * in which there is no available ebda information. In such
-         * case, just skip it
-         */
-        if (!ebda_addr) {
-                ebda_size = 0;
-                return;
-        }
-
-        ebda_addr <<= 4;
-
-        ebda_size = *(unsigned short *)__va(ebda_addr);
-
-        /* Round EBDA up to pages */
-        if (ebda_size == 0)
-                ebda_size = 1;
-        ebda_size <<= 10;
-        ebda_size = round_up(ebda_size + (ebda_addr & ~PAGE_MASK), PAGE_SIZE);
-        if (ebda_size > 64*1024)
-                ebda_size = 64*1024;
-}
-
 /* Overridden in paravirt.c if CONFIG_PARAVIRT */
 void __attribute__((weak)) __init memory_setup(void)
 {
@@ -349,8 +314,6 @@ void __init setup_arch(char **cmdline_p)
 
         check_efer();
 
-        discover_ebda();
-
         init_memory_mapping(0, (end_pfn_map << PAGE_SHIFT));
         if (efi_enabled)
                 efi_init();
@@ -397,33 +360,7 @@ void __init setup_arch(char **cmdline_p)
         contig_initmem_init(0, end_pfn);
 #endif
 
-        /* Reserve direct mapping */
-        reserve_bootmem_generic(table_start << PAGE_SHIFT,
-                                (table_end - table_start) << PAGE_SHIFT);
-
-        /* reserve kernel */
-        reserve_bootmem_generic(__pa_symbol(&_text),
-                                __pa_symbol(&_end) - __pa_symbol(&_text));
-
-        /*
-         * reserve physical page 0 - it's a special BIOS page on many boxes,
-         * enabling clean reboots, SMP operation, laptop functions.
-         */
-        reserve_bootmem_generic(0, PAGE_SIZE);
-
-        /* reserve ebda region */
-        if (ebda_addr)
-                reserve_bootmem_generic(ebda_addr, ebda_size);
-#ifdef CONFIG_NUMA
-        /* reserve nodemap region */
-        if (nodemap_addr)
-                reserve_bootmem_generic(nodemap_addr, nodemap_size);
-#endif
-
-#ifdef CONFIG_SMP
-        /* Reserve SMP trampoline */
-        reserve_bootmem_generic(SMP_TRAMPOLINE_BASE, 2*PAGE_SIZE);
-#endif
+        early_res_to_bootmem();
 
 #ifdef CONFIG_ACPI_SLEEP
         /*
@@ -453,6 +390,8 @@ void __init setup_arch(char **cmdline_p)
                         initrd_start = ramdisk_image + PAGE_OFFSET;
                         initrd_end = initrd_start+ramdisk_size;
                 } else {
+                        /* Assumes everything on node 0 */
+                        free_bootmem(ramdisk_image, ramdisk_size);
                         printk(KERN_ERR "initrd extends beyond end of memory "
                                "(0x%08lx > 0x%08lx)\ndisabling initrd\n",
                                ramdisk_end, end_of_mem);
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 05f12c527b02..8198840c3dcb 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -176,7 +176,8 @@ __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t prot)
         set_pte_phys(address, phys, prot);
 }
 
-unsigned long __meminitdata table_start, table_end;
+static unsigned long __initdata table_start;
+static unsigned long __meminitdata table_end;
 
 static __meminit void *alloc_low_page(unsigned long *phys)
 { 
@@ -387,6 +388,8 @@ void __init_refok init_memory_mapping(unsigned long start, unsigned long end)
         if (!after_bootmem)
                 mmu_cr4_features = read_cr4();
         __flush_tlb_all();
+
+        reserve_early(table_start << PAGE_SHIFT, table_end << PAGE_SHIFT);
 }
 
 #ifndef CONFIG_NUMA
diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
index 37d429beba96..5d24dc1ec237 100644
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -102,6 +102,7 @@ static int __init allocate_cachealigned_memnodemap(void)
         }
         pad_addr = (nodemap_addr + pad) & ~pad;
         memnodemap = phys_to_virt(pad_addr);
+        reserve_early(nodemap_addr, nodemap_addr + nodemap_size);
 
         printk(KERN_DEBUG "NUMA: Allocated memnodemap from %lx - %lx\n",
                nodemap_addr, nodemap_addr + nodemap_size);
diff --git a/include/asm-x86/e820_64.h b/include/asm-x86/e820_64.h
index ff36f434f00b..51e4170f9ca5 100644
--- a/include/asm-x86/e820_64.h
+++ b/include/asm-x86/e820_64.h
@@ -41,8 +41,8 @@ extern void finish_e820_parsing(void);
 extern struct e820map e820;
 extern void update_e820(void);
 
-extern unsigned ebda_addr, ebda_size;
-extern unsigned long nodemap_addr, nodemap_size;
+extern void reserve_early(unsigned long start, unsigned long end);
+extern void early_res_to_bootmem(void);
 
 #endif/*!__ASSEMBLY__*/
 
diff --git a/include/asm-x86/proto.h b/include/asm-x86/proto.h
index 3c6fb89f1120..68563c0709ac 100644
--- a/include/asm-x86/proto.h
+++ b/include/asm-x86/proto.h
@@ -22,8 +22,6 @@ extern void syscall32_cpu_init(void);
 
 extern void check_efer(void);
 
-extern unsigned long table_start, table_end;
-
 extern int reboot_force;
 
 long do_arch_prctl(struct task_struct *task, int code, unsigned long addr);