From 1ab4d3079d29e9ebee0c85f1aec14a3b1df8f679 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Wed, 13 Mar 2024 15:08:10 +0000 Subject: [mp] Define an API for multiprocessor functions Define an API for executing very limited functions on application processors in a multiprocessor system, along with an x86-only implementation. The normal iPXE runtime environment is effectively non-existent on application processors. There is no ability to make firmware calls (e.g. to write to a console), and there may be no stack space available. Signed-off-by: Michael Brown --- src/arch/arm/include/bits/mp.h | 12 +++ src/arch/loong64/include/bits/mp.h | 12 +++ src/arch/x86/core/mpcall.S | 197 +++++++++++++++++++++++++++++++++++++ src/arch/x86/include/bits/mp.h | 12 +++ src/config/defaults/efi.h | 1 + src/config/defaults/linux.h | 1 + src/config/defaults/pcbios.h | 1 + src/core/mp.c | 67 +++++++++++++ src/core/null_mp.c | 37 +++++++ src/include/ipxe/mp.h | 154 +++++++++++++++++++++++++++++ src/include/ipxe/null_mp.h | 36 +++++++ 11 files changed, 530 insertions(+) create mode 100644 src/arch/arm/include/bits/mp.h create mode 100644 src/arch/loong64/include/bits/mp.h create mode 100644 src/arch/x86/core/mpcall.S create mode 100644 src/arch/x86/include/bits/mp.h create mode 100644 src/core/mp.c create mode 100644 src/core/null_mp.c create mode 100644 src/include/ipxe/mp.h create mode 100644 src/include/ipxe/null_mp.h diff --git a/src/arch/arm/include/bits/mp.h b/src/arch/arm/include/bits/mp.h new file mode 100644 index 00000000..e7d4c0c1 --- /dev/null +++ b/src/arch/arm/include/bits/mp.h @@ -0,0 +1,12 @@ +#ifndef _BITS_MP_H +#define _BITS_MP_H + +/** @file + * + * ARM-specific multiprocessor API implementation + * + */ + +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); + +#endif /* _BITS_MP_H */ diff --git a/src/arch/loong64/include/bits/mp.h b/src/arch/loong64/include/bits/mp.h new file mode 100644 index 00000000..fef2fd59 --- /dev/null +++ b/src/arch/loong64/include/bits/mp.h @@ -0,0 +1,12 @@ +#ifndef _BITS_MP_H +#define _BITS_MP_H + +/** @file + * + * LoongArch64-specific multiprocessor API implementation + * + */ + +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); + +#endif /* _BITS_MP_H */ diff --git a/src/arch/x86/core/mpcall.S b/src/arch/x86/core/mpcall.S new file mode 100644 index 00000000..f2a3bf90 --- /dev/null +++ b/src/arch/x86/core/mpcall.S @@ -0,0 +1,197 @@ +/* + * Copyright (C) 2024 Michael Brown . + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + * + * You can also choose to distribute this program under the terms of + * the Unmodified Binary Distribution Licence (as given in the file + * COPYING.UBDL), provided that you have satisfied its requirements. + */ + + FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ) + +/** @file + * + * Multiprocessor functions + * + */ + + .section ".note.GNU-stack", "", @progbits + .text + +/* Selectively assemble code for 32-bit/64-bit builds */ +#if defined ( __x86_64__ ) && ! defined ( PLATFORM_pcbios ) +#define codemp code64 +#define DI rdi +#define SP rsp +#define if32 if 0 +#define if64 if 1 +#else +#define codemp code32 +#define DI edi +#define SP esp +#define if32 if 1 +#define if64 if 0 +#endif + +/* Standard features CPUID leaf */ +#define CPUID_FEATURES 0x00000001 + +/* x2APIC is supported */ +#define CPUID_FEATURES_ECX_X2APIC 0x00200000 + +/* Extended topology enumeration CPUID leaf */ +#define CPUID_XT_ENUM 0x0000000b + +/* + * Call multiprocessor function from C code + * + * Parameters: + * 4(%esp)/%rdi Multiprocessor function + * 8(%esp)/%rsi Opaque data pointer + */ + .section ".text.mp_call", "ax", @progbits + .codemp + .globl mp_call +mp_call: +.if64 /* Preserve registers, load incoming parameters into registers */ + pushq %rax + pushq %rcx + pushq %rdx + pushq %rbx + pushq %rsp + pushq %rbp + pushq %rsi + pushq %rdi + pushq %r8 + pushq %r9 + pushq %r10 + pushq %r11 + pushq %r12 + pushq %r13 + pushq %r14 + pushq %r15 +.else + pushal + movl 36(%esp), %eax + movl 40(%esp), %edx +.endif + /* Call multiprocessor function */ + call mp_jump + +.if64 /* Restore registers and return */ + popq %r15 + popq %r14 + popq %r13 + popq %r12 + popq %r11 + popq %r10 + popq %r9 + popq %r8 + popq %rdi + popq %rsi + popq %rbp + leaq 8(%rsp), %rsp /* discard */ + popq %rbx + popq %rdx + popq %rcx + popq %rax +.else + popal +.endif + ret + .size mp_call, . - mp_call + +/* + * Jump to multiprocessor function + * + * Parameters: + * %eax/%rdi Multiprocessor function + * %edx/%rsi Opaque data pointer + * %esp/%rsp Stack, or NULL to halt AP upon completion + * + * Obtain the CPU identifier (i.e. the APIC ID) and perform a tail + * call into the specified multiprocessor function. + * + * This code may run with no stack on an application processor. + */ + .section ".text.mp_jump", "ax", @progbits + .codemp + .globl mp_jump +mp_jump: +.if32 /* Move function parameters to available registers */ + movl %eax, %edi + movl %edx, %esi +.endif + + /* Get 8-bit APIC ID and x2APIC feature bit */ + movl $CPUID_FEATURES, %eax + cpuid + shrl $24, %ebx + movl %ebx, %edx + + /* Get 32-bit x2APIC ID if applicable */ + testl $CPUID_FEATURES_ECX_X2APIC, %ecx + jz 1f + movl $CPUID_XT_ENUM, %eax + xorl %ecx, %ecx + cpuid +1: + +.if64 /* Tail call to function */ + movq %rdi, %rax + movq %rsi, %rdi + movl %edx, %esi + jmp *%rax +.else + movl %esi, %eax + jmp *%edi +.endif + .size mp_jump, . - mp_jump + +/* + * Update maximum CPU identifier + * + * Parameters: + * %eax/%rdi Pointer to shared maximum APIC ID + * %edx/%rsi CPU identifier (APIC ID) + * %esp/%rsp Stack, or NULL to halt AP upon completion + * + * This code may run with no stack on an application processor. + */ + .section ".text.mp_update_max_cpuid", "ax", @progbits + .codemp + .globl mp_update_max_cpuid +mp_update_max_cpuid: +.if32 /* Move function parameters to available registers */ + movl %eax, %edi + movl %edx, %esi +.endif + /* Update maximum APIC ID (atomically) */ + movl (%DI), %eax +1: cmpl %esi, %eax + jae 2f + lock cmpxchgl %esi, (%DI) + jnz 1b +2: + /* Return to caller (if stack exists), or halt application processor */ + test %SP, %SP + jz 3f + ret +3: cli + hlt + jmp 3b + .size mp_update_max_cpuid, . - mp_update_max_cpuid diff --git a/src/arch/x86/include/bits/mp.h b/src/arch/x86/include/bits/mp.h new file mode 100644 index 00000000..fe466b09 --- /dev/null +++ b/src/arch/x86/include/bits/mp.h @@ -0,0 +1,12 @@ +#ifndef _BITS_MP_H +#define _BITS_MP_H + +/** @file + * + * x86-specific multiprocessor API implementation + * + */ + +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); + +#endif /* _BITS_MP_H */ diff --git a/src/config/defaults/efi.h b/src/config/defaults/efi.h index e39d475b..9c0f238a 100644 --- a/src/config/defaults/efi.h +++ b/src/config/defaults/efi.h @@ -25,6 +25,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); #define REBOOT_EFI #define ACPI_EFI #define FDT_EFI +#define MPAPI_NULL #define NET_PROTO_IPV6 /* IPv6 protocol */ #define NET_PROTO_LLDP /* Link Layer Discovery protocol */ diff --git a/src/config/defaults/linux.h b/src/config/defaults/linux.h index 21de2a2e..fae144b3 100644 --- a/src/config/defaults/linux.h +++ b/src/config/defaults/linux.h @@ -22,6 +22,7 @@ FILE_LICENCE ( GPL2_OR_LATER ); #define PCIAPI_LINUX #define DMAAPI_FLAT #define ACPI_LINUX +#define MPAPI_NULL #define DRIVERS_LINUX diff --git a/src/config/defaults/pcbios.h b/src/config/defaults/pcbios.h index ee342d41..968bd82a 100644 --- a/src/config/defaults/pcbios.h +++ b/src/config/defaults/pcbios.h @@ -24,6 +24,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); #define TIME_RTC #define REBOOT_PCBIOS #define ACPI_RSDP +#define MPAPI_NULL #ifdef __x86_64__ #define IOMAP_PAGES diff --git a/src/core/mp.c b/src/core/mp.c new file mode 100644 index 00000000..146d70a6 --- /dev/null +++ b/src/core/mp.c @@ -0,0 +1,67 @@ +/* + * Copyright (C) 2024 Michael Brown . + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + * + * You can also choose to distribute this program under the terms of + * the Unmodified Binary Distribution Licence (as given in the file + * COPYING.UBDL), provided that you have satisfied its requirements. + */ + +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); + +/** @file + * + * Multiprocessor functions + * + */ + +#include +#include + +/** Time to wait for application processors */ +#define MP_MAX_CPUID_WAIT_MS 10 + +/** + * Get boot CPU identifier + * + * @ret id Boot CPU identifier + */ +unsigned int mp_boot_cpuid ( void ) { + unsigned int max = 0; + + /* Update maximum to accommodate boot processor */ + mp_exec_boot ( mp_update_max_cpuid, &max ); + DBGC ( &mp_call, "MP boot processor ID is %#x\n", max ); + + return max; +} + +/** + * Get maximum CPU identifier + * + * @ret max Maximum CPU identifier + */ +unsigned int mp_max_cpuid ( void ) { + unsigned int max = mp_boot_cpuid(); + + /* Update maximum to accommodate application processors */ + mp_start_all ( mp_update_max_cpuid, &max ); + mdelay ( MP_MAX_CPUID_WAIT_MS ); + DBGC ( &mp_call, "MP observed maximum CPU ID is %#x\n", max ); + + return max; +} diff --git a/src/core/null_mp.c b/src/core/null_mp.c new file mode 100644 index 00000000..0fa69303 --- /dev/null +++ b/src/core/null_mp.c @@ -0,0 +1,37 @@ +/* + * Copyright (C) 2024 Michael Brown . + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + * + * You can also choose to distribute this program under the terms of + * the Unmodified Binary Distribution Licence (as given in the file + * COPYING.UBDL), provided that you have satisfied its requirements. + */ + +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); + +/** + * @file + * + * Null multiprocessor API + * + */ + +#include + +PROVIDE_MPAPI_INLINE ( null, mp_address ); +PROVIDE_MPAPI_INLINE ( null, mp_exec_boot ); +PROVIDE_MPAPI_INLINE ( null, mp_start_all ); diff --git a/src/include/ipxe/mp.h b/src/include/ipxe/mp.h new file mode 100644 index 00000000..a3657490 --- /dev/null +++ b/src/include/ipxe/mp.h @@ -0,0 +1,154 @@ +#ifndef _IPXE_MP_H +#define _IPXE_MP_H + +/** @file + * + * Multiprocessor functions + * + */ + +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); + +#include +#include +#include + +/** + * An address within the address space for a multiprocessor function + * + * Application processors may be started in a different address space + * from the normal iPXE runtime environment. For example: under + * legacy BIOS the application processors will use flat 32-bit + * physical addressing (with no paging or virtual address offset). + */ +typedef unsigned long mp_addr_t; + +/** A multiprocessor function + * + * @v opaque Opaque data pointer + * @v cpuid CPU identifier + * + * iPXE does not set up a normal multiprocessor environment. In + * particular, there is no support for dispatching code to individual + * processors and there is no per-CPU stack allocation. + * + * Multiprocessor code must be prepared to run wth no stack space (and + * with a zero stack pointer). Functions may use the CPU identifier + * to construct a pointer to per-CPU result storage. + * + * Multiprocessor functions are permitted to overwrite all registers + * apart from the stack pointer. On exit, the function should check + * the stack pointer value: if zero then the function should halt the + * CPU, if non-zero then the function should return in the normal way. + * + * Multiprocessor functions do not have access to any capabilities + * typically provided by the firmware: they cannot, for example, write + * any console output. + * + * All parameters are passed in registers, since there may be no stack + * available. These functions cannot be called directly from C code. + */ +typedef void ( mp_func_t ) ( mp_addr_t opaque, unsigned int cpuid ); + +/** + * Call a multiprocessor function from C code on the current CPU + * + * @v func Multiprocessor function + * @v opaque Opaque data pointer + * + * This function must be provided for each CPU architecture to bridge + * the normal C ABI to the iPXE multiprocessor function ABI. It must + * therefore preserve any necessary registers, determine the CPU + * identifier, call the multiprocessor function (which may destroy any + * registers other than the stack pointer), restore registers, and + * return to the C caller. + * + * This function must be called from within the multiprocessor address + * space (e.g. with flat 32-bit physical addressing for BIOS). It can + * be called directly from C code if the multiprocessor address space + * is identical to the address space used for C code (e.g. under EFI, + * where everything uses flat physical addresses). + */ +extern void __asmcall mp_call ( mp_addr_t func, mp_addr_t opaque ); + +/** + * Calculate static inline multiprocessor API function name + * + * @v _prefix Subsystem prefix + * @v _api_func API function + * @ret _subsys_func Subsystem API function + */ +#define MPAPI_INLINE( _subsys, _api_func ) \ + SINGLE_API_INLINE ( MPAPI_PREFIX_ ## _subsys, _api_func ) + +/** + * Provide a multiprocessor API implementation + * + * @v _prefix Subsystem prefix + * @v _api_func API function + * @v _func Implementing function + */ +#define PROVIDE_MPAPI( _subsys, _api_func, _func ) \ + PROVIDE_SINGLE_API ( MPAPI_PREFIX_ ## _subsys, _api_func, _func ) + +/** + * Provide a static inline multiprocessor API implementation + * + * @v _prefix Subsystem prefix + * @v _api_func API function + */ +#define PROVIDE_MPAPI_INLINE( _subsys, _api_func ) \ + PROVIDE_SINGLE_API_INLINE ( MPAPI_PREFIX_ ## _subsys, _api_func ) + +/* Include all architecture-independent multiprocessor API headers */ +#include + +/* Include all architecture-dependent multiprocessor API headers */ +#include + +/** + * Calculate address as seen by a multiprocessor function + * + * @v address Address in normal iPXE address space + * @ret address Address in application processor address space + */ +mp_addr_t mp_address ( void *address ); + +/** + * Execute a multiprocessor function on the boot processor + * + * @v func Multiprocessor function + * @v opaque Opaque data pointer + * + * This is a blocking operation: the call will return only when the + * multiprocessor function exits. + */ +void mp_exec_boot ( mp_func_t func, void *opaque ); + +/** + * Start a multiprocessor function on all application processors + * + * @v func Multiprocessor function + * @v opaque Opaque data pointer + * + * This is a non-blocking operation: it is the caller's responsibility + * to provide a way to determine when the multiprocessor function has + * finished executing and halted its CPU. + */ +void mp_start_all ( mp_func_t func, void *opaque ); + +/** + * Update maximum observed CPU identifier + * + * @v opaque Opaque data pointer + * @v cpuid CPU identifier + * + * This may be invoked on each processor to update a shared maximum + * CPU identifier value. + */ +extern mp_func_t mp_update_max_cpuid; + +extern unsigned int mp_boot_cpuid ( void ); +extern unsigned int mp_max_cpuid ( void ); + +#endif /* _IPXE_MP_H */ diff --git a/src/include/ipxe/null_mp.h b/src/include/ipxe/null_mp.h new file mode 100644 index 00000000..f89da5d9 --- /dev/null +++ b/src/include/ipxe/null_mp.h @@ -0,0 +1,36 @@ +#ifndef _IPXE_NULL_MP_H +#define _IPXE_NULL_MP_H + +/** @file + * + * Null multiprocessor API implementation + * + */ + +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); + +#ifdef MPAPI_NULL +#define MPAPI_PREFIX_null +#else +#define MPAPI_PREFIX_null __null_ +#endif + +static inline __attribute__ (( always_inline )) mp_addr_t +MPAPI_INLINE ( null, mp_address ) ( void *address ) { + + return ( ( mp_addr_t ) address ); +} + +static inline __attribute__ (( always_inline )) void +MPAPI_INLINE ( null, mp_exec_boot ) ( mp_func_t func __unused, + void *opaque __unused ) { + /* Do nothing */ +} + +static inline __attribute__ (( always_inline )) void +MPAPI_INLINE ( null, mp_start_all ) ( mp_func_t func __unused, + void *opaque __unused ) { + /* Do nothing */ +} + +#endif /* _IPXE_NULL_MP_H */ -- cgit v1.2.3-55-g7522