1 files changed, 93 insertions, 86 deletions

diff --git a/arch/x86/kernel/microcode_amd.c b/arch/x86/kernel/microcode_amd.c
index 9129c6981c5b..384990d2c54d 100644
--- a/arch/x86/kernel/microcode_amd.c
+++ b/arch/x86/kernel/microcode_amd.c
@@ -89,27 +89,76 @@ static int collect_cpu_info_amd(int cpu, struct cpu_signature *csig)
         return 0;
 }
 
-static int get_matching_microcode(int cpu, struct microcode_header_amd *mc_hdr,
-                                  int rev)
+static unsigned int verify_ucode_size(int cpu, u32 patch_size,
+                                      unsigned int size)
 {
-        unsigned int current_cpu_id;
-        u16 equiv_cpu_id = 0;
-        unsigned int i = 0;
+        struct cpuinfo_x86 *c = &cpu_data(cpu);
+        u32 max_size;
+
+#define F1XH_MPB_MAX_SIZE 2048
+#define F14H_MPB_MAX_SIZE 1824
+#define F15H_MPB_MAX_SIZE 4096
+
+        switch (c->x86) {
+        case 0x14:
+                max_size = F14H_MPB_MAX_SIZE;
+                break;
+        case 0x15:
+                max_size = F15H_MPB_MAX_SIZE;
+                break;
+        default:
+                max_size = F1XH_MPB_MAX_SIZE;
+                break;
+        }
+
+        if (patch_size > min_t(u32, size, max_size)) {
+                pr_err("patch size mismatch\n");
+                return 0;
+        }
+
+        return patch_size;
+}
+
+static u16 find_equiv_id(void)
+{
+        unsigned int current_cpu_id, i = 0;
 
         BUG_ON(equiv_cpu_table == NULL);
+
         current_cpu_id = cpuid_eax(0x00000001);
 
         while (equiv_cpu_table[i].installed_cpu != 0) {
-                if (current_cpu_id == equiv_cpu_table[i].installed_cpu) {
-                        equiv_cpu_id = equiv_cpu_table[i].equiv_cpu;
-                        break;
-                }
+                if (current_cpu_id == equiv_cpu_table[i].installed_cpu)
+                        return equiv_cpu_table[i].equiv_cpu;
+
                 i++;
         }
+        return 0;
+}
 
+/*
+ * we signal a good patch is found by returning its size > 0
+ */
+static int get_matching_microcode(int cpu, const u8 *ucode_ptr,
+                                  unsigned int leftover_size, int rev,
+                                  unsigned int *current_size)
+{
+        struct microcode_header_amd *mc_hdr;
+        unsigned int actual_size;
+        u16 equiv_cpu_id;
+
+        /* size of the current patch we're staring at */
+        *current_size = *(u32 *)(ucode_ptr + 4) + SECTION_HDR_SIZE;
+
+        equiv_cpu_id = find_equiv_id();
         if (!equiv_cpu_id)
                 return 0;
 
+        /*
+         * let's look at the patch header itself now
+         */
+        mc_hdr = (struct microcode_header_amd *)(ucode_ptr + SECTION_HDR_SIZE);
+
         if (mc_hdr->processor_rev_id != equiv_cpu_id)
                 return 0;
 
@@ -123,7 +172,20 @@ static int get_matching_microcode(int cpu, struct microcode_header_amd *mc_hdr,
         if (mc_hdr->patch_id <= rev)
                 return 0;
 
-        return 1;
+        /*
+         * now that the header looks sane, verify its size
+         */
+        actual_size = verify_ucode_size(cpu, *current_size, leftover_size);
+        if (!actual_size)
+                return 0;
+
+        /* clear the patch buffer */
+        memset(patch, 0, PAGE_SIZE);
+
+        /* all looks ok, get the binary patch */
+        get_ucode_data(patch, ucode_ptr + SECTION_HDR_SIZE, actual_size);
+
+        return actual_size;
 }
 
 static int apply_microcode_amd(int cpu)
@@ -158,63 +220,6 @@ static int apply_microcode_amd(int cpu)
         return 0;
 }
 
-static unsigned int verify_ucode_size(int cpu, const u8 *buf, unsigned int size)
-{
-        struct cpuinfo_x86 *c = &cpu_data(cpu);
-        u32 max_size, actual_size;
-
-#define F1XH_MPB_MAX_SIZE 2048
-#define F14H_MPB_MAX_SIZE 1824
-#define F15H_MPB_MAX_SIZE 4096
-
-        switch (c->x86) {
-        case 0x14:
-                max_size = F14H_MPB_MAX_SIZE;
-                break;
-        case 0x15:
-                max_size = F15H_MPB_MAX_SIZE;
-                break;
-        default:
-                max_size = F1XH_MPB_MAX_SIZE;
-                break;
-        }
-
-        actual_size = *(u32 *)(buf + 4);
-
-        if (actual_size + SECTION_HDR_SIZE > size || actual_size > max_size) {
-                pr_err("section size mismatch\n");
-                return 0;
-        }
-
-        return actual_size;
-}
-
-static struct microcode_header_amd *
-get_next_ucode(int cpu, const u8 *buf, unsigned int size, unsigned int *mc_size)
-{
-        struct microcode_header_amd *mc = NULL;
-        unsigned int actual_size = 0;
-
-        if (*(u32 *)buf != UCODE_UCODE_TYPE) {
-                pr_err("invalid type field in container file section header\n");
-                goto out;
-        }
-
-        actual_size = verify_ucode_size(cpu, buf, size);
-        if (!actual_size)
-                goto out;
-
-        mc = vzalloc(actual_size);
-        if (!mc)
-                goto out;
-
-        get_ucode_data(mc, buf + SECTION_HDR_SIZE, actual_size);
-        *mc_size = actual_size + SECTION_HDR_SIZE;
-
-out:
-        return mc;
-}
-
 static int install_equiv_cpu_table(const u8 *buf)
 {
         unsigned int *ibuf = (unsigned int *)buf;
@@ -250,36 +255,38 @@ generic_load_microcode(int cpu, const u8 *data, size_t size)
 {
         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
         struct microcode_header_amd *mc_hdr = NULL;
-        unsigned int mc_size, leftover;
+        unsigned int mc_size, leftover, current_size = 0;
         int offset;
         const u8 *ucode_ptr = data;
         void *new_mc = NULL;
         unsigned int new_rev = uci->cpu_sig.rev;
-        enum ucode_state state = UCODE_OK;
+        enum ucode_state state = UCODE_ERROR;
 
         offset = install_equiv_cpu_table(ucode_ptr);
         if (offset < 0) {
                 pr_err("failed to create equivalent cpu table\n");
-                return UCODE_ERROR;
+                goto out;
         }
-
         ucode_ptr += offset;
         leftover = size - offset;
 
-        while (leftover) {
-                mc_hdr = get_next_ucode(cpu, ucode_ptr, leftover, &mc_size);
-                if (!mc_hdr)
-                        break;
+        if (*(u32 *)ucode_ptr != UCODE_UCODE_TYPE) {
+                pr_err("invalid type field in container file section header\n");
+                goto free_table;
+        }
 
-                if (get_matching_microcode(cpu, mc_hdr, new_rev)) {
-                        vfree(new_mc);
+        while (leftover) {
+                mc_size = get_matching_microcode(cpu, ucode_ptr, leftover,
+                                                 new_rev, &current_size);
+                if (mc_size) {
+                        mc_hdr  = patch;
+                        new_mc  = patch;
                         new_rev = mc_hdr->patch_id;
-                        new_mc  = mc_hdr;
-                } else
-                        vfree(mc_hdr);
-
-                ucode_ptr += mc_size;
-                leftover  -= mc_size;
+                        leftover -= mc_size;
+                } else {
+                        ucode_ptr += current_size;
+                        leftover  -= current_size;
+                }
         }
 
         if (!new_mc) {
@@ -288,18 +295,19 @@ generic_load_microcode(int cpu, const u8 *data, size_t size)
         }
 
         if (!leftover) {
-                vfree(uci->mc);
                 uci->mc = new_mc;
+                state = UCODE_OK;
                 pr_debug("CPU%d update ucode (0x%08x -> 0x%08x)\n",
                          cpu, uci->cpu_sig.rev, new_rev);
         } else {
-                vfree(new_mc);
+                new_mc = NULL;
                 state = UCODE_ERROR;
         }
 
 free_table:
         free_equiv_cpu_table();
 
+out:
         return state;
 }
 
@@ -340,7 +348,6 @@ static void microcode_fini_cpu_amd(int cpu)
 {
         struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 
-        vfree(uci->mc);
         uci->mc = NULL;
 }