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linux/arch/s390/kernel/early.c
Christian Borntraeger 92e6ecf392 [S390] Fix hypervisor detection for KVM
Currently we use the cpuid (via STIDP instruction) to recognize LPAR,
z/VM and KVM.
The architecture states, that bit 0-7 of STIDP returns all zero, and
if STIDP is executed in a virtual machine, the VM operating system
will replace bits 0-7 with FF.

KVM should not use FE to distinguish z/VM from KVM for interested
guests. The proper way to detect the hypervisor is the STSI (Store
System Information) instruction, which return information about the
hypervisors via function code 3, selector1=2, selector2=2.

This patch changes the detection routine of Linux to use STSI instead
of STIDP. This detection is earlier than bootmem, we have to use a
static buffer. Since STSI expects a 4kb block (4kb aligned) this
patch also changes the init.data alignment for s390. As this section
will be freed during boot, this should be no problem.

Patch is tested with LPAR, z/VM, KVM on LPAR, and KVM under z/VM.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:09 +01:00

397 lines
8.7 KiB
C

/*
* arch/s390/kernel/early.c
*
* Copyright IBM Corp. 2007
* Author(s): Hongjie Yang <hongjie@us.ibm.com>,
* Heiko Carstens <heiko.carstens@de.ibm.com>
*/
#include <linux/compiler.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/lockdep.h>
#include <linux/module.h>
#include <linux/pfn.h>
#include <linux/uaccess.h>
#include <asm/ebcdic.h>
#include <asm/ipl.h>
#include <asm/lowcore.h>
#include <asm/processor.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/sysinfo.h>
#include <asm/cpcmd.h>
#include <asm/sclp.h>
#include "entry.h"
/*
* Create a Kernel NSS if the SAVESYS= parameter is defined
*/
#define DEFSYS_CMD_SIZE 128
#define SAVESYS_CMD_SIZE 32
char kernel_nss_name[NSS_NAME_SIZE + 1];
static void __init setup_boot_command_line(void);
#ifdef CONFIG_SHARED_KERNEL
int __init savesys_ipl_nss(char *cmd, const int cmdlen);
asm(
" .section .init.text,\"ax\",@progbits\n"
" .align 4\n"
" .type savesys_ipl_nss, @function\n"
"savesys_ipl_nss:\n"
#ifdef CONFIG_64BIT
" stmg 6,15,48(15)\n"
" lgr 14,3\n"
" sam31\n"
" diag 2,14,0x8\n"
" sam64\n"
" lgr 2,14\n"
" lmg 6,15,48(15)\n"
#else
" stm 6,15,24(15)\n"
" lr 14,3\n"
" diag 2,14,0x8\n"
" lr 2,14\n"
" lm 6,15,24(15)\n"
#endif
" br 14\n"
" .size savesys_ipl_nss, .-savesys_ipl_nss\n");
static noinline __init void create_kernel_nss(void)
{
unsigned int i, stext_pfn, eshared_pfn, end_pfn, min_size;
#ifdef CONFIG_BLK_DEV_INITRD
unsigned int sinitrd_pfn, einitrd_pfn;
#endif
int response;
size_t len;
char *savesys_ptr;
char upper_command_line[COMMAND_LINE_SIZE];
char defsys_cmd[DEFSYS_CMD_SIZE];
char savesys_cmd[SAVESYS_CMD_SIZE];
/* Do nothing if we are not running under VM */
if (!MACHINE_IS_VM)
return;
/* Convert COMMAND_LINE to upper case */
for (i = 0; i < strlen(boot_command_line); i++)
upper_command_line[i] = toupper(boot_command_line[i]);
savesys_ptr = strstr(upper_command_line, "SAVESYS=");
if (!savesys_ptr)
return;
savesys_ptr += 8; /* Point to the beginning of the NSS name */
for (i = 0; i < NSS_NAME_SIZE; i++) {
if (savesys_ptr[i] == ' ' || savesys_ptr[i] == '\0')
break;
kernel_nss_name[i] = savesys_ptr[i];
}
stext_pfn = PFN_DOWN(__pa(&_stext));
eshared_pfn = PFN_DOWN(__pa(&_eshared));
end_pfn = PFN_UP(__pa(&_end));
min_size = end_pfn << 2;
sprintf(defsys_cmd, "DEFSYS %s 00000-%.5X EW %.5X-%.5X SR %.5X-%.5X",
kernel_nss_name, stext_pfn - 1, stext_pfn, eshared_pfn - 1,
eshared_pfn, end_pfn);
#ifdef CONFIG_BLK_DEV_INITRD
if (INITRD_START && INITRD_SIZE) {
sinitrd_pfn = PFN_DOWN(__pa(INITRD_START));
einitrd_pfn = PFN_UP(__pa(INITRD_START + INITRD_SIZE));
min_size = einitrd_pfn << 2;
sprintf(defsys_cmd, "%s EW %.5X-%.5X", defsys_cmd,
sinitrd_pfn, einitrd_pfn);
}
#endif
sprintf(defsys_cmd, "%s EW MINSIZE=%.7iK PARMREGS=0-13",
defsys_cmd, min_size);
sprintf(savesys_cmd, "SAVESYS %s \n IPL %s",
kernel_nss_name, kernel_nss_name);
__cpcmd(defsys_cmd, NULL, 0, &response);
if (response != 0) {
kernel_nss_name[0] = '\0';
return;
}
len = strlen(savesys_cmd);
ASCEBC(savesys_cmd, len);
response = savesys_ipl_nss(savesys_cmd, len);
/* On success: response is equal to the command size,
* max SAVESYS_CMD_SIZE
* On error: response contains the numeric portion of cp error message.
* for SAVESYS it will be >= 263
*/
if (response > SAVESYS_CMD_SIZE) {
kernel_nss_name[0] = '\0';
return;
}
/* re-setup boot command line with new ipl vm parms */
ipl_update_parameters();
setup_boot_command_line();
ipl_flags = IPL_NSS_VALID;
}
#else /* CONFIG_SHARED_KERNEL */
static inline void create_kernel_nss(void) { }
#endif /* CONFIG_SHARED_KERNEL */
/*
* Clear bss memory
*/
static noinline __init void clear_bss_section(void)
{
memset(__bss_start, 0, __bss_stop - __bss_start);
}
/*
* Initialize storage key for kernel pages
*/
static noinline __init void init_kernel_storage_key(void)
{
unsigned long end_pfn, init_pfn;
end_pfn = PFN_UP(__pa(&_end));
for (init_pfn = 0 ; init_pfn < end_pfn; init_pfn++)
page_set_storage_key(init_pfn << PAGE_SHIFT, PAGE_DEFAULT_KEY);
}
static __initdata struct sysinfo_3_2_2 vmms __aligned(PAGE_SIZE);
static noinline __init void detect_machine_type(void)
{
/* No VM information? Looks like LPAR */
if (stsi(&vmms, 3, 2, 2) == -ENOSYS)
return;
if (!vmms.count)
return;
/* Running under KVM? If not we assume z/VM */
if (!memcmp(vmms.vm[0].cpi, "\xd2\xe5\xd4", 3))
machine_flags |= MACHINE_FLAG_KVM;
else
machine_flags |= MACHINE_FLAG_VM;
}
static __init void early_pgm_check_handler(void)
{
unsigned long addr;
const struct exception_table_entry *fixup;
addr = S390_lowcore.program_old_psw.addr;
fixup = search_exception_tables(addr & PSW_ADDR_INSN);
if (!fixup)
disabled_wait(0);
S390_lowcore.program_old_psw.addr = fixup->fixup | PSW_ADDR_AMODE;
}
static noinline __init void setup_lowcore_early(void)
{
psw_t psw;
psw.mask = PSW_BASE_BITS | PSW_DEFAULT_KEY;
psw.addr = PSW_ADDR_AMODE | (unsigned long) s390_base_ext_handler;
S390_lowcore.external_new_psw = psw;
psw.addr = PSW_ADDR_AMODE | (unsigned long) s390_base_pgm_handler;
S390_lowcore.program_new_psw = psw;
s390_base_pgm_handler_fn = early_pgm_check_handler;
}
static noinline __init void setup_hpage(void)
{
#ifndef CONFIG_DEBUG_PAGEALLOC
unsigned int facilities;
facilities = stfl();
if (!(facilities & (1UL << 23)) || !(facilities & (1UL << 29)))
return;
machine_flags |= MACHINE_FLAG_HPAGE;
__ctl_set_bit(0, 23);
#endif
}
static __init void detect_mvpg(void)
{
#ifndef CONFIG_64BIT
int rc;
asm volatile(
" la 0,0\n"
" mvpg %2,%2\n"
"0: la %0,0\n"
"1:\n"
EX_TABLE(0b,1b)
: "=d" (rc) : "0" (-EOPNOTSUPP), "a" (0) : "memory", "cc", "0");
if (!rc)
machine_flags |= MACHINE_FLAG_MVPG;
#endif
}
static __init void detect_ieee(void)
{
#ifndef CONFIG_64BIT
int rc, tmp;
asm volatile(
" efpc %1,0\n"
"0: la %0,0\n"
"1:\n"
EX_TABLE(0b,1b)
: "=d" (rc), "=d" (tmp): "0" (-EOPNOTSUPP) : "cc");
if (!rc)
machine_flags |= MACHINE_FLAG_IEEE;
#endif
}
static __init void detect_csp(void)
{
#ifndef CONFIG_64BIT
int rc;
asm volatile(
" la 0,0\n"
" la 1,0\n"
" la 2,4\n"
" csp 0,2\n"
"0: la %0,0\n"
"1:\n"
EX_TABLE(0b,1b)
: "=d" (rc) : "0" (-EOPNOTSUPP) : "cc", "0", "1", "2");
if (!rc)
machine_flags |= MACHINE_FLAG_CSP;
#endif
}
static __init void detect_diag9c(void)
{
unsigned int cpu_address;
int rc;
cpu_address = stap();
asm volatile(
" diag %2,0,0x9c\n"
"0: la %0,0\n"
"1:\n"
EX_TABLE(0b,1b)
: "=d" (rc) : "0" (-EOPNOTSUPP), "d" (cpu_address) : "cc");
if (!rc)
machine_flags |= MACHINE_FLAG_DIAG9C;
}
static __init void detect_diag44(void)
{
#ifdef CONFIG_64BIT
int rc;
asm volatile(
" diag 0,0,0x44\n"
"0: la %0,0\n"
"1:\n"
EX_TABLE(0b,1b)
: "=d" (rc) : "0" (-EOPNOTSUPP) : "cc");
if (!rc)
machine_flags |= MACHINE_FLAG_DIAG44;
#endif
}
static __init void detect_machine_facilities(void)
{
#ifdef CONFIG_64BIT
unsigned int facilities;
facilities = stfl();
if (facilities & (1 << 28))
machine_flags |= MACHINE_FLAG_IDTE;
if (facilities & (1 << 23))
machine_flags |= MACHINE_FLAG_PFMF;
if (facilities & (1 << 4))
machine_flags |= MACHINE_FLAG_MVCOS;
#endif
}
static __init void rescue_initrd(void)
{
#ifdef CONFIG_BLK_DEV_INITRD
/*
* Move the initrd right behind the bss section in case it starts
* within the bss section. So we don't overwrite it when the bss
* section gets cleared.
*/
if (!INITRD_START || !INITRD_SIZE)
return;
if (INITRD_START >= (unsigned long) __bss_stop)
return;
memmove(__bss_stop, (void *) INITRD_START, INITRD_SIZE);
INITRD_START = (unsigned long) __bss_stop;
#endif
}
/* Set up boot command line */
static void __init setup_boot_command_line(void)
{
char *parm = NULL;
/* copy arch command line */
strlcpy(boot_command_line, COMMAND_LINE, ARCH_COMMAND_LINE_SIZE);
boot_command_line[ARCH_COMMAND_LINE_SIZE - 1] = 0;
/* append IPL PARM data to the boot command line */
if (MACHINE_IS_VM) {
parm = boot_command_line + strlen(boot_command_line);
*parm++ = ' ';
get_ipl_vmparm(parm);
if (parm[0] == '=')
memmove(boot_command_line, parm + 1, strlen(parm));
}
}
/*
* Save ipl parameters, clear bss memory, initialize storage keys
* and create a kernel NSS at startup if the SAVESYS= parm is defined
*/
void __init startup_init(void)
{
ipl_save_parameters();
rescue_initrd();
clear_bss_section();
init_kernel_storage_key();
lockdep_init();
lockdep_off();
sort_main_extable();
setup_lowcore_early();
detect_machine_type();
ipl_update_parameters();
setup_boot_command_line();
create_kernel_nss();
detect_mvpg();
detect_ieee();
detect_csp();
detect_diag9c();
detect_diag44();
detect_machine_facilities();
setup_hpage();
sclp_facilities_detect();
detect_memory_layout(memory_chunk);
lockdep_on();
}