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author | Michael Brown <mcb30@ipxe.org> | 2024-03-13 15:08:10 +0000 |
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committer | Michael Brown <mcb30@ipxe.org> | 2024-03-15 13:26:53 +0000 |
commit | 1ab4d3079d29e9ebee0c85f1aec14a3b1df8f679 (patch) | |
tree | 2e8989a1d7654459760bcc4d94e9cabb4e167ca0 /src/include/ipxe | |
parent | df2f23e333601e587f72c68cb7b7b116796f9d3c (diff) | |
download | ipxe-1ab4d3079d29e9ebee0c85f1aec14a3b1df8f679.zip ipxe-1ab4d3079d29e9ebee0c85f1aec14a3b1df8f679.tar.gz ipxe-1ab4d3079d29e9ebee0c85f1aec14a3b1df8f679.tar.bz2 |
[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 <mcb30@ipxe.org>
Diffstat (limited to 'src/include/ipxe')
-rw-r--r-- | src/include/ipxe/mp.h | 154 | ||||
-rw-r--r-- | src/include/ipxe/null_mp.h | 36 |
2 files changed, 190 insertions, 0 deletions
diff --git a/src/include/ipxe/mp.h b/src/include/ipxe/mp.h new file mode 100644 index 0000000..a365749 --- /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 <stdint.h> +#include <ipxe/api.h> +#include <config/defaults.h> + +/** + * 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 <ipxe/null_mp.h> + +/* Include all architecture-dependent multiprocessor API headers */ +#include <bits/mp.h> + +/** + * 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 0000000..f89da5d --- /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 */ |