[PATCH] ppc64: tell firmware about kernel capabilities

On pSeries systems, according to the platform architecture specs, we are
supposed to be supplying a structure to firmware that tells firmware about
our capabilities, such as which version of the data structures that
describe available memory we are expecting to see.  The way we end up
having to supply this data structure is a bit gross, since it was designed
for AIX and doesn't suit us very well.  This patch adds the code to supply
this data structure to the firmware.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 107 insertions, 0 deletions

diff --git a/arch/ppc64/kernel/prom_init.c b/arch/ppc64/kernel/prom_init.c
index 8dffa9ae262..b0b784f9a4e 100644
--- a/arch/ppc64/kernel/prom_init.c
+++ b/arch/ppc64/kernel/prom_init.c
@@ -493,6 +493,113 @@ static void __init early_cmdline_parse(void)
 }
 
 /*
+ * To tell the firmware what our capabilities are, we have to pass
+ * it a fake 32-bit ELF header containing a couple of PT_NOTE sections
+ * that contain structures that contain the actual values.
+ */
+static struct fake_elf {
+        Elf32_Ehdr      elfhdr;
+        Elf32_Phdr      phdr[2];
+        struct chrpnote {
+                u32     namesz;
+                u32     descsz;
+                u32     type;
+                char    name[8];        /* "PowerPC" */
+                struct chrpdesc {
+                        u32     real_mode;
+                        u32     real_base;
+                        u32     real_size;
+                        u32     virt_base;
+                        u32     virt_size;
+                        u32     load_base;
+                } chrpdesc;
+        } chrpnote;
+        struct rpanote {
+                u32     namesz;
+                u32     descsz;
+                u32     type;
+                char    name[24];       /* "IBM,RPA-Client-Config" */
+                struct rpadesc {
+                        u32     lpar_affinity;
+                        u32     min_rmo_size;
+                        u32     min_rmo_percent;
+                        u32     max_pft_size;
+                        u32     splpar;
+                        u32     min_load;
+                        u32     new_mem_def;
+                        u32     ignore_me;
+                } rpadesc;
+        } rpanote;
+} fake_elf = {
+        .elfhdr = {
+                .e_ident = { 0x7f, 'E', 'L', 'F',
+                             ELFCLASS32, ELFDATA2MSB, EV_CURRENT },
+                .e_type = ET_EXEC,      /* yeah right */
+                .e_machine = EM_PPC,
+                .e_version = EV_CURRENT,
+                .e_phoff = offsetof(struct fake_elf, phdr),
+                .e_phentsize = sizeof(Elf32_Phdr),
+                .e_phnum = 2
+        },
+        .phdr = {
+                [0] = {
+                        .p_type = PT_NOTE,
+                        .p_offset = offsetof(struct fake_elf, chrpnote),
+                        .p_filesz = sizeof(struct chrpnote)
+                }, [1] = {
+                        .p_type = PT_NOTE,
+                        .p_offset = offsetof(struct fake_elf, rpanote),
+                        .p_filesz = sizeof(struct rpanote)
+                }
+        },
+        .chrpnote = {
+                .namesz = sizeof("PowerPC"),
+                .descsz = sizeof(struct chrpdesc),
+                .type = 0x1275,
+                .name = "PowerPC",
+                .chrpdesc = {
+                        .real_mode = ~0U,       /* ~0 means "don't care" */
+                        .real_base = ~0U,
+                        .real_size = ~0U,
+                        .virt_base = ~0U,
+                        .virt_size = ~0U,
+                        .load_base = ~0U
+                },
+        },
+        .rpanote = {
+                .namesz = sizeof("IBM,RPA-Client-Config"),
+                .descsz = sizeof(struct rpadesc),
+                .type = 0x12759999,
+                .name = "IBM,RPA-Client-Config",
+                .rpadesc = {
+                        .lpar_affinity = 0,
+                        .min_rmo_size = 64,     /* in megabytes */
+                        .min_rmo_percent = 0,
+                        .max_pft_size = 48,     /* 2^48 bytes max PFT size */
+                        .splpar = 1,
+                        .min_load = ~0U,
+                        .new_mem_def = 0
+                }
+        }
+};
+
+static void __init prom_send_capabilities(void)
+{
+        unsigned long offset = reloc_offset();
+        ihandle elfloader;
+        int ret;
+
+        elfloader = call_prom("open", 1, 1, ADDR("/packages/elf-loader"));
+        if (elfloader == 0) {
+                prom_printf("couldn't open /packages/elf-loader\n");
+                return;
+        }
+        ret = call_prom("call-method", 3, 1, ADDR("process-elf-header"),
+                        elfloader, ADDR(&fake_elf));
+        call_prom("close", 1, 0, elfloader);
+}
+
+/*
  * Memory allocation strategy... our layout is normally:
  *
  *  at 14Mb or more we vmlinux, then a gap and initrd. In some rare cases, initrd