From 28bb9ee13aa0ee4c57dc3568f539cc84920b43aa Mon Sep 17 00:00:00 2001 From: "jschopp@austin.ibm.com" Date: Mon, 1 Feb 2010 12:50:48 +0000 Subject: powerpc: Add static fields to ibm,client-architecture call This patch adds 2 fields to the ibm_architecture_vec array. The first of these fields indicates the number of cores which Linux can boot. It does not account for SMT, so it may result in cpus assigned to Linux which cannot be booted. A second patch follows that dynamically updates this for SMT. The second field just indicates that our OS is Linux, and not another OS. The system may or may not use this hint to performance tune settings for Linux. Signed-off-by: Joel Schopp Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/prom_init.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/kernel/prom_init.c') diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c index bafac2e41ae1..59d5bd1c064d 100644 --- a/arch/powerpc/kernel/prom_init.c +++ b/arch/powerpc/kernel/prom_init.c @@ -654,6 +654,9 @@ static void __init early_cmdline_parse(void) #define OV5_CMO 0x00 #endif +/* Option Vector 6: IBM PAPR hints */ +#define OV6_LINUX 0x02 /* Linux is our OS */ + /* * The architecture vector has an array of PVR mask/value pairs, * followed by # option vectors - 1, followed by the option vectors. @@ -665,7 +668,7 @@ static unsigned char ibm_architecture_vec[] = { W(0xffffffff), W(0x0f000003), /* all 2.06-compliant */ W(0xffffffff), W(0x0f000002), /* all 2.05-compliant */ W(0xfffffffe), W(0x0f000001), /* all 2.04-compliant and earlier */ - 5 - 1, /* 5 option vectors */ + 6 - 1, /* 6 option vectors */ /* option vector 1: processor architectures supported */ 3 - 2, /* length */ @@ -697,12 +700,24 @@ static unsigned char ibm_architecture_vec[] = { 0, /* don't halt */ /* option vector 5: PAPR/OF options */ - 5 - 2, /* length */ + 13 - 2, /* length */ 0, /* don't ignore, don't halt */ OV5_LPAR | OV5_SPLPAR | OV5_LARGE_PAGES | OV5_DRCONF_MEMORY | OV5_DONATE_DEDICATE_CPU | OV5_MSI, 0, OV5_CMO, + 0, + 0, + 0, + 0, + W(NR_CPUS), /* number of cores supported*/ + + /* option vector 6: IBM PAPR hints */ + 4 - 2, /* length */ + 0, + 0, + OV6_LINUX, + }; /* Old method - ELF header with PT_NOTE sections */ -- cgit v1.2.3 From efec959f63de850fbd2442189f7dfc9c38efe251 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Thu, 4 Feb 2010 14:33:54 +1100 Subject: powerpc/pseries: Pass more accurate number of supported cores to firmware Updated variant of a patch by Joel Schopp. The field containing the number of supported cores which we pass to firmware via the ibm,client-architecture call was set by a previous patch statically as high as is possible (NR_CPUS). However, that value isn't quite right for a system that supports multiple threads per core, thus permitting the firmware to assign more cores to a Linux partition than it can really cope with. This patch improves it by using the device-tree to determine the number of threads supported by the processors in order to adjust the value passed to firmware. Signed-off-by: Joel Schopp Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/prom_init.c | 64 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 63 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/kernel/prom_init.c') diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c index 59d5bd1c064d..5f306c4946e5 100644 --- a/arch/powerpc/kernel/prom_init.c +++ b/arch/powerpc/kernel/prom_init.c @@ -710,7 +710,12 @@ static unsigned char ibm_architecture_vec[] = { 0, 0, 0, - W(NR_CPUS), /* number of cores supported*/ + /* WARNING: The offset of the "number of cores" field below + * must match by the macro below. Update the definition if + * the structure layout changes. + */ +#define IBM_ARCH_VEC_NRCORES_OFFSET 100 + W(NR_CPUS), /* number of cores supported */ /* option vector 6: IBM PAPR hints */ 4 - 2, /* length */ @@ -807,13 +812,70 @@ static struct fake_elf { } }; +static int __init prom_count_smt_threads(void) +{ + phandle node; + char type[64]; + unsigned int plen; + + /* Pick up th first CPU node we can find */ + for (node = 0; prom_next_node(&node); ) { + type[0] = 0; + prom_getprop(node, "device_type", type, sizeof(type)); + + if (strcmp(type, RELOC("cpu"))) + continue; + /* + * There is an entry for each smt thread, each entry being + * 4 bytes long. All cpus should have the same number of + * smt threads, so return after finding the first. + */ + plen = prom_getproplen(node, "ibm,ppc-interrupt-server#s"); + if (plen == PROM_ERROR) + break; + plen >>= 2; + prom_debug("Found 0x%x smt threads per core\n", (unsigned long)plen); + + /* Sanity check */ + if (plen < 1 || plen > 64) { + prom_printf("Threads per core 0x%x out of bounds, assuming 1\n", + (unsigned long)plen); + return 1; + } + return plen; + } + prom_debug("No threads found, assuming 1 per core\n"); + + return 1; + +} + + static void __init prom_send_capabilities(void) { ihandle elfloader, root; prom_arg_t ret; + u32 *cores; root = call_prom("open", 1, 1, ADDR("/")); if (root != 0) { + /* We need to tell the FW about the number of cores we support. + * + * To do that, we count the number of threads on the first core + * (we assume this is the same for all cores) and use it to + * divide NR_CPUS. + */ + cores = (u32 *)PTRRELOC(&ibm_architecture_vec[IBM_ARCH_VEC_NRCORES_OFFSET]); + if (*cores != NR_CPUS) { + prom_printf("WARNING ! " + "ibm_architecture_vec structure inconsistent: 0x%x !\n", + *cores); + } else { + *cores = NR_CPUS / prom_count_smt_threads(); + prom_printf("Max number of cores passed to firmware: 0x%x\n", + (unsigned long)*cores); + } + /* try calling the ibm,client-architecture-support method */ prom_printf("Calling ibm,client-architecture-support..."); if (call_prom_ret("call-method", 3, 2, &ret, -- cgit v1.2.3