#include <grub/machine/kernel.h>
#endif
-/* The maximum heap size we're going to claim */
+/* The maximum heap size we're going to claim at boot. Not used by sparc. */
#ifdef __i386__
#define HEAP_MAX_SIZE (unsigned long) (64 * 1024 * 1024)
-#else
+#else /* __powerpc__ */
#define HEAP_MAX_SIZE (unsigned long) (32 * 1024 * 1024)
#endif
+/* RMO max. address at 768 MB */
+#define RMO_ADDR_MAX (grub_uint64_t) (768 * 1024 * 1024)
+
+/*
+ * The amount of OF space we will not claim here so as to leave space for
+ * the loader and linux to service early allocations.
+ *
+ * In 2021, Daniel Axtens claims that we should leave at least 128MB to
+ * ensure we can load a stock kernel and initrd on a pseries guest with
+ * a 512MB real memory area under PowerVM.
+ */
+#define RUNTIME_MIN_SPACE (128UL * 1024 * 1024)
+
extern char _start[];
extern char _end[];
+ GRUB_KERNEL_MACHINE_STACK_SIZE), 0x200000);
}
#else
-/* Helper for grub_claim_heap. */
+/* Helpers for mm on powerpc. */
+
+/*
+ * How much memory does OF believe exists in total?
+ *
+ * This isn't necessarily the true total. It can be the total memory
+ * accessible in real mode for a pseries guest, for example.
+ */
+static grub_uint64_t rmo_top;
+
static int
-heap_init (grub_uint64_t addr, grub_uint64_t len, grub_memory_type_t type,
- void *data)
+count_free (grub_uint64_t addr, grub_uint64_t len, grub_memory_type_t type,
+ void *data)
{
- unsigned long *total = data;
+ if (type != GRUB_MEMORY_AVAILABLE)
+ return 0;
+
+ /* Do not consider memory beyond 4GB */
+ if (addr > 0xffffffffULL)
+ return 0;
+
+ if (addr + len > 0xffffffffULL)
+ len = 0xffffffffULL - addr;
+
+ *(grub_uint32_t *) data += len;
+
+ return 0;
+}
+
+static int
+regions_claim (grub_uint64_t addr, grub_uint64_t len, grub_memory_type_t type,
+ unsigned int flags, void *data)
+{
+ grub_uint32_t total = *(grub_uint32_t *) data;
+ grub_uint64_t linux_rmo_save;
if (type != GRUB_MEMORY_AVAILABLE)
return 0;
+ /* Do not consider memory beyond 4GB */
+ if (addr > 0xffffffffULL)
+ return 0;
+
+ if (addr + len > 0xffffffffULL)
+ len = 0xffffffffULL - addr;
+
if (grub_ieee1275_test_flag (GRUB_IEEE1275_FLAG_NO_PRE1_5M_CLAIM))
{
if (addr + len <= 0x180000)
}
}
- /* Never exceed HEAP_MAX_SIZE */
- if (*total + len > HEAP_MAX_SIZE)
- len = HEAP_MAX_SIZE - *total;
-
/* In theory, firmware should already prevent this from happening by not
listing our own image in /memory/available. The check below is intended
as a safeguard in case that doesn't happen. However, it doesn't protect
len = 0;
}
+ /*
+ * Linux likes to claim memory at min(RMO top, 768MB) and works down
+ * without reference to /memory/available. (See prom_init.c::alloc_down)
+ *
+ * If this block contains min(RMO top, 768MB), do not claim below that for
+ * at least a few MB (this is where RTAS, SML and potentially TCEs live).
+ *
+ * We also need to leave enough space for the DT in the RMA. (See
+ * prom_init.c::alloc_up)
+ *
+ * Finally, we also want to make sure that when grub loads the kernel,
+ * it isn't going to use up all the memory we're trying to reserve! So
+ * enforce our entire RUNTIME_MIN_SPACE here:
+ *
+ * |---------- Top of memory ----------|
+ * | |
+ * | available |
+ * | |
+ * |---------- 768 MB ----------|
+ * | |
+ * | reserved |
+ * | |
+ * |--- 768 MB - runtime min space ---|
+ * | |
+ * | available |
+ * | |
+ * |---------- 0 MB ----------|
+ *
+ * Edge cases:
+ *
+ * - Total memory less than RUNTIME_MIN_SPACE: only claim up to HEAP_MAX_SIZE.
+ * (enforced elsewhere)
+ *
+ * - Total memory between RUNTIME_MIN_SPACE and 768MB:
+ *
+ * |---------- Top of memory ----------|
+ * | |
+ * | reserved |
+ * | |
+ * |---- top - runtime min space ----|
+ * | |
+ * | available |
+ * | |
+ * |---------- 0 MB ----------|
+ *
+ * This by itself would not leave us with RUNTIME_MIN_SPACE of free bytes: if
+ * rmo_top < 768MB, we will almost certainly have FW claims in the reserved
+ * region. We try to address that elsewhere: grub_ieee1275_mm_add_region will
+ * not call us if the resulting free space would be less than RUNTIME_MIN_SPACE.
+ */
+ linux_rmo_save = grub_min (RMO_ADDR_MAX, rmo_top) - RUNTIME_MIN_SPACE;
+ if (rmo_top > RUNTIME_MIN_SPACE)
+ {
+ if (rmo_top <= RMO_ADDR_MAX)
+ {
+ if (addr > linux_rmo_save)
+ {
+ grub_dprintf ("ieee1275", "rejecting region in RUNTIME_MIN_SPACE reservation (%llx)\n",
+ addr);
+ return 0;
+ }
+ else if (addr + len > linux_rmo_save)
+ {
+ grub_dprintf ("ieee1275", "capping region: (%llx -> %llx) -> (%llx -> %llx)\n",
+ addr, addr + len, addr, rmo_top - RUNTIME_MIN_SPACE);
+ len = linux_rmo_save - addr;
+ }
+ }
+ else
+ {
+ /*
+ * we order these cases to prefer higher addresses and avoid some
+ * splitting issues
+ */
+ if (addr < RMO_ADDR_MAX && (addr + len) > RMO_ADDR_MAX)
+ {
+ grub_dprintf ("ieee1275",
+ "adjusting region for RUNTIME_MIN_SPACE: (%llx -> %llx) -> (%llx -> %llx)\n",
+ addr, addr + len, RMO_ADDR_MAX, addr + len);
+ len = (addr + len) - RMO_ADDR_MAX;
+ addr = RMO_ADDR_MAX;
+ }
+ else if ((addr < linux_rmo_save) && ((addr + len) > linux_rmo_save))
+ {
+ grub_dprintf ("ieee1275", "capping region: (%llx -> %llx) -> (%llx -> %llx)\n",
+ addr, addr + len, addr, linux_rmo_save);
+ len = linux_rmo_save - addr;
+ }
+ else if (addr >= linux_rmo_save && (addr + len) <= RMO_ADDR_MAX)
+ {
+ grub_dprintf ("ieee1275", "rejecting region in RUNTIME_MIN_SPACE reservation (%llx)\n",
+ addr);
+ return 0;
+ }
+ }
+ }
+ if (flags & GRUB_MM_ADD_REGION_CONSECUTIVE && len < total)
+ return 0;
+
+ if (len > total)
+ len = total;
+
if (len)
{
grub_err_t err;
if (err)
return err;
grub_mm_init_region ((void *) (grub_addr_t) addr, len);
+ total -= len;
}
- *total += len;
- if (*total >= HEAP_MAX_SIZE)
+ *(grub_uint32_t *) data = total;
+
+ if (total == 0)
return 1;
return 0;
}
+static int
+heap_init (grub_uint64_t addr, grub_uint64_t len, grub_memory_type_t type,
+ void *data)
+{
+ return regions_claim (addr, len, type, GRUB_MM_ADD_REGION_NONE, data);
+}
+
+static int
+region_claim (grub_uint64_t addr, grub_uint64_t len, grub_memory_type_t type,
+ void *data)
+{
+ return regions_claim (addr, len, type, GRUB_MM_ADD_REGION_CONSECUTIVE, data);
+}
+
+static grub_err_t
+grub_ieee1275_mm_add_region (grub_size_t size, unsigned int flags)
+{
+ grub_uint32_t free_memory = 0;
+ grub_uint32_t avail = 0;
+ grub_uint32_t total;
+
+ grub_dprintf ("ieee1275", "mm requested region of size %x, flags %x\n",
+ size, flags);
+
+ /*
+ * Update free memory each time, which is a bit inefficient but guards us
+ * against a situation where some OF driver goes out to firmware for
+ * memory and we don't realise.
+ */
+ grub_machine_mmap_iterate (count_free, &free_memory);
+
+ /* Ensure we leave enough space to boot. */
+ if (free_memory <= RUNTIME_MIN_SPACE + size)
+ {
+ grub_dprintf ("ieee1275", "Cannot satisfy allocation and retain minimum runtime space\n");
+ return GRUB_ERR_OUT_OF_MEMORY;
+ }
+
+ if (free_memory > RUNTIME_MIN_SPACE)
+ avail = free_memory - RUNTIME_MIN_SPACE;
+
+ grub_dprintf ("ieee1275", "free = 0x%x available = 0x%x\n", free_memory, avail);
+
+ if (flags & GRUB_MM_ADD_REGION_CONSECUTIVE)
+ {
+ /* first try rounding up hard for the sake of speed */
+ total = grub_max (ALIGN_UP (size, 1024 * 1024) + 1024 * 1024, 32 * 1024 * 1024);
+ total = grub_min (avail, total);
+
+ grub_dprintf ("ieee1275", "looking for %x bytes of memory (%x requested)\n", total, size);
+
+ grub_machine_mmap_iterate (region_claim, &total);
+ grub_dprintf ("ieee1275", "get memory from fw %s\n", total == 0 ? "succeeded" : "failed");
+
+ if (total != 0)
+ {
+ total = grub_min (avail, size);
+
+ grub_dprintf ("ieee1275", "fallback for %x bytes of memory (%x requested)\n", total, size);
+
+ grub_machine_mmap_iterate (region_claim, &total);
+ grub_dprintf ("ieee1275", "fallback from fw %s\n", total == 0 ? "succeeded" : "failed");
+ }
+ }
+ else
+ {
+ /* provide padding for a grub_mm_header_t and region */
+ total = grub_min (avail, size);
+ grub_machine_mmap_iterate (heap_init, &total);
+ grub_dprintf ("ieee1275", "get noncontig memory from fw %s\n", total == 0 ? "succeeded" : "failed");
+ }
+
+ if (total == 0)
+ return GRUB_ERR_NONE;
+ else
+ return GRUB_ERR_OUT_OF_MEMORY;
+}
+
/*
* How much memory does OF believe it has? (regardless of whether
* it's accessible or not)
static void
grub_claim_heap (void)
{
- unsigned long total = 0;
+ grub_err_t err;
+ grub_uint32_t total = HEAP_MAX_SIZE;
+
+ err = grub_ieee1275_total_mem (&rmo_top);
+
+ /*
+ * If we cannot size the available memory, we can't be sure we're leaving
+ * space for the kernel, initrd and things Linux loads early in boot. So only
+ * allow further allocations from firmware on success
+ */
+ if (err == GRUB_ERR_NONE)
+ grub_mm_add_region_fn = grub_ieee1275_mm_add_region;
#if defined(__powerpc__)
if (grub_ieee1275_test_flag (GRUB_IEEE1275_FLAG_CAN_TRY_CAS_FOR_MORE_MEMORY))
{
- grub_uint64_t rma_size;
- grub_err_t err;
-
- err = grub_ieee1275_total_mem (&rma_size);
/* if we have an error, don't call CAS, just hope for the best */
- if (err == GRUB_ERR_NONE && rma_size < (512 * 1024 * 1024))
+ if (err == GRUB_ERR_NONE && rmo_top < (512 * 1024 * 1024))
grub_ieee1275_ibm_cas ();
}
#endif
projects / thirdparty / grub.git / commitdiff
