Changeset d59718e in mainline

Timestamp:

2018-10-21T21:57:23Z (6 years ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

cfdeedc

Parents:

566457ad

Message:

Move stack to always be after all boot allocations

This works around an issue on pcc32.
Since this is not a proper solution and I've so far been unable
to determine root cause, I'm also opening a ticket to track it.

Files:

• boot/arch/ppc32/src/asm.S (modified) (3 diffs)
• boot/arch/ppc32/src/main.c (modified) (1 diff)
• kernel/generic/src/main/main.c (modified) (1 diff)

boot/arch/ppc32/src/asm.S

@@ -403 +403 @@
         # pc = kernel's entry point (r7)
         # r3 = bootinfo (physical address)
-        # sprg0 = BOOT_OFFSET
         # sprg3 = physical memory size
         # sp = 0 (enforces the usage of sprg0 as exception stack)
@@ -409 +408 @@
         mtspr srr0, r7
 
-        lis r31, BOOT_OFFSET@ha
-        addi r31, r31, BOOT_OFFSET@l
+        # Clear sprg0. Kernel will set it.
+        li r31, 0
         mtsprg0 r31
 
@@ -416 +415 @@
         # the physical memory size, get the lower 4 bytes
 
+        // FIXME: unchecked magic offset
         lwz r31, 4(r3)
         mtsprg3 r31

boot/arch/ppc32/src/main.c

@@ -97 +97 @@
         size_t pages = (balloc_start + ALIGN_UP(BALLOC_MAX_SIZE, PAGE_SIZE)) >>
             PAGE_WIDTH;
+
+        printf(" Boot allocations area: %p - %p\n", (void *) balloc_start,
+            (void *) (pages << PAGE_WIDTH));
+
+        if ((pages << PAGE_WIDTH) >= (uintptr_t) loader_address_pa) {
+                printf("Boot allocations overlap loader area.\n");
+                printf("The boot image is too large. Halting.\n");
+                halt();
+        }
+
         void *transtable;
         void *transtable_pa;

kernel/generic/src/main/main.c

@@ -172 +172 @@
         config.kernel_size =
             ALIGN_UP((uintptr_t) kdata_end - config.base, PAGE_SIZE);
+
+        /* Place the stack after the kernel, init and ballocs. */
+        config.stack_base = config.base + config.kernel_size;
         config.stack_size = STACK_SIZE;
-
-        /* Initialy the stack is placed just after the kernel */
-        config.stack_base = config.base + config.kernel_size;
 
         /* Avoid placing stack on top of init */
         size_t i;
         for (i = 0; i < init.cnt; i++) {
-                if (overlaps(KA2PA(config.stack_base), config.stack_size,
-                    init.tasks[i].paddr, init.tasks[i].size)) {
-                        /*
-                         * The init task overlaps with the memory behind the
-                         * kernel image so it must be in low memory and we can
-                         * use PA2KA on the init task's physical address.
-                         */
-                        config.stack_base = ALIGN_UP(
-                            PA2KA(init.tasks[i].paddr) + init.tasks[i].size,
-                            config.stack_size);
-                }
+                uintptr_t p = init.tasks[i].paddr + init.tasks[i].size;
+                uintptr_t bottom = PA2KA(ALIGN_UP(p, PAGE_SIZE));
+
+                if (config.stack_base < bottom)
+                        config.stack_base = bottom;
         }
 
         /* Avoid placing stack on top of boot allocations. */
         if (ballocs.size) {
-                if (PA_OVERLAPS(config.stack_base, config.stack_size,
-                    ballocs.base, ballocs.size))
-                        config.stack_base = ALIGN_UP(ballocs.base +
-                            ballocs.size, PAGE_SIZE);
+                uintptr_t bottom =
+                    ALIGN_UP(ballocs.base + ballocs.size, PAGE_SIZE);
+                if (config.stack_base < bottom)
+                        config.stack_base = bottom;
         }