isa-l/include/aarch64_multibinary.h

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#ifndef __AARCH64_MULTIBINARY_H__
#define __AARCH64_MULTIBINARY_H__
#ifndef __aarch64__
#error "This file is for aarch64 only"
#endif
#include "aarch64_label.h"
#ifdef __ASSEMBLY__
/**
 * # mbin_interface : the wrapper layer for isal-l api
 *
 * ## references:
 * * https://sourceware.org/git/gitweb.cgi?p=glibc.git;a=blob;f=sysdeps/aarch64/dl-trampoline.S
 * * http://infocenter.arm.com/help/topic/com.arm.doc.ihi0055b/IHI0055B_aapcs64.pdf
 * * https://static.docs.arm.com/ihi0057/b/IHI0057B_aadwarf64.pdf?_ga=2.80574487.1870739014.1564969896-1634778941.1548729310
 *
 * ## Usage:
 * 	1. Define dispather function
 * 	2. name must be \name\()_dispatcher
 * 	3. Prototype should be *"void * \name\()_dispatcher"*
 * 	4. The dispather should return the right function pointer , revision and a string information .
 **/
.macro mbin_interface name:req
	.extern cdecl(\name\()_dispatcher)
	.data
	.balign 8
	.global cdecl(\name\()_dispatcher_info)
#ifndef __APPLE__
	.type   \name\()_dispatcher_info,%object
#endif
	cdecl(\name\()_dispatcher_info):
		.quad   \name\()_mbinit         //func_entry
#ifndef __APPLE__
	.size   \name\()_dispatcher_info,. - \name\()_dispatcher_info
#endif
	.balign 8
	.text
	\name\()_mbinit:
		//save lp fp, sub sp
		.cfi_startproc
		stp     x29, x30, [sp, -224]!

		//add cfi directive to avoid GDB bt cmds error
		//set cfi(Call Frame Information)
		.cfi_def_cfa_offset 224
		.cfi_offset 	    29, -224
		.cfi_offset 	    30, -216

		//save parameter/result/indirect result registers
		stp	x8,  x9,  [sp,   16]
		.cfi_offset 	    8, -208
		.cfi_offset 	    9, -200
		stp	x0,  x1,  [sp,   32]
		.cfi_offset 	    0, -192
		.cfi_offset 	    1, -184
		stp	x2,  x3,  [sp,   48]
		.cfi_offset 	    2, -176
		.cfi_offset 	    3, -168
		stp	x4,  x5,  [sp,   64]
		.cfi_offset 	    4, -160
		.cfi_offset 	    5, -152
		stp	x6,  x7,  [sp,   80]
		.cfi_offset 	    6, -144
		.cfi_offset 	    7, -136
		stp	q0,  q1,  [sp,   96]
		.cfi_offset 	   64, -128
		.cfi_offset 	   65, -112
		stp	q2,  q3,  [sp,  128]
		.cfi_offset 	   66,  -96
		.cfi_offset 	   67,  -80
		stp	q4,  q5,  [sp,  160]
		.cfi_offset 	   68,  -64
		.cfi_offset 	   69,  -48
		stp	q6,  q7,  [sp,  192]
		.cfi_offset 	   70,  -32
		.cfi_offset 	   71,  -16

		/**
		 * The dispatcher functions have the following prototype:
		 * 	void * function_dispatcher(void)
		 * As the dispatcher is returning a struct, by the AAPCS,
		 */


		bl cdecl(\name\()_dispatcher)
		//restore temp/indirect result registers
		ldp	x8,  x9,  [sp,    16]
		.cfi_restore 8
		.cfi_restore 9

		//	save function entry
		str	x0,  [x9]

		//restore parameter/result registers
		ldp	x0,  x1,  [sp,    32]
		.cfi_restore 0
		.cfi_restore 1
		ldp	x2,  x3,  [sp,    48]
		.cfi_restore 2
		.cfi_restore 3
		ldp	x4,  x5,  [sp,    64]
		.cfi_restore 4
		.cfi_restore 5
		ldp	x6,  x7,  [sp,    80]
		.cfi_restore 6
		.cfi_restore 7
		ldp	q0,  q1,  [sp,    96]
		.cfi_restore 64
		.cfi_restore 65
		ldp	q2,  q3,  [sp,   128]
		.cfi_restore 66
		.cfi_restore 67
		ldp	q4,  q5,  [sp,   160]
		.cfi_restore 68
		.cfi_restore 69
		ldp	q6,  q7,  [sp,   192]
		.cfi_restore 70
		.cfi_restore 71
		//save lp fp and sp
		ldp     x29, x30, [sp], 224
		//restore cfi setting
		.cfi_restore 30
		.cfi_restore 29
		.cfi_def_cfa_offset 0
		.cfi_endproc

	.global cdecl(\name)
#ifndef __APPLE__
	.type \name,%function
#endif
	.align  2
	cdecl(\name\()):
#ifndef __APPLE__
		adrp    x9, :got:\name\()_dispatcher_info
		ldr     x9, [x9, #:got_lo12:\name\()_dispatcher_info]
#else
		adrp    x9, cdecl(\name\()_dispatcher_info)@GOTPAGE
		ldr     x9, [x9, #cdecl(\name\()_dispatcher_info)@GOTPAGEOFF]
#endif
		ldr     x10,[x9]
		br      x10
#ifndef __APPLE__
	.size \name,. - \name
#endif
.endm

/**
 * mbin_interface_base is used for the interfaces which have only
 * noarch implementation
 */
.macro mbin_interface_base name:req, base:req
	.extern \base
	.data
	.balign 8
	.global cdecl(\name\()_dispatcher_info)
#ifndef __APPLE__
	.type   \name\()_dispatcher_info,%object
#endif
	cdecl(\name\()_dispatcher_info):
		.quad   \base         //func_entry
#ifndef __APPLE__
	.size   \name\()_dispatcher_info,. - \name\()_dispatcher_info
#endif
	.balign 8
	.text
	.global cdecl(\name)
#ifndef __APPLE__
	.type \name,%function
#endif
	.align  2
	cdecl(\name\()):
#ifndef __APPLE__
		adrp    x9, :got:cdecl(_\name\()_dispatcher_info)
		ldr     x9, [x9, #:got_lo12:cdecl(_\name\()_dispatcher_info)]
#else
		adrp    x9, cdecl(_\name\()_dispatcher_info)@GOTPAGE
		ldr     x9, [x9, #cdecl(_\name\()_dispatcher_info)@GOTPAGEOFF]
#endif
		ldr     x10,[x9]
		br      x10
#ifndef __APPLE__
	.size \name,. - \name
#endif
.endm

#else /* __ASSEMBLY__ */
#include <stdint.h>
#if defined(__linux__)
#include <sys/auxv.h>
#include <asm/hwcap.h>
#elif defined(__APPLE__)
#define SYSCTL_PMULL_KEY "hw.optional.arm.FEAT_PMULL" // from macOS 12 FEAT_* sysctl infos are available
#define SYSCTL_CRC32_KEY "hw.optional.armv8_crc32"
#define SYSCTL_SVE_KEY "hw.optional.arm.FEAT_SVE" // this one is just a guess and need to check macOS update
#include <sys/sysctl.h>
#include <stddef.h>
static inline int sysctlEnabled(const char* name){
	int enabled;
	size_t size = sizeof(enabled);
	int status = sysctlbyname(name, &enabled, &size, NULL, 0);
	return status ? 0 : enabled;
}
#endif


#define DEFINE_INTERFACE_DISPATCHER(name)                               \
	void * name##_dispatcher(void)

#define PROVIDER_BASIC(name)                                            \
	PROVIDER_INFO(name##_base)

#define DO_DIGNOSTIC(x)	_Pragma GCC diagnostic ignored "-W"#x
#define DO_PRAGMA(x) _Pragma (#x)
#define DIGNOSTIC_IGNORE(x) DO_PRAGMA(GCC diagnostic ignored #x)
#define DIGNOSTIC_PUSH()	DO_PRAGMA(GCC diagnostic push)
#define DIGNOSTIC_POP()		DO_PRAGMA(GCC diagnostic pop)


#define PROVIDER_INFO(_func_entry)                                  	\
	({	DIGNOSTIC_PUSH()					\
		DIGNOSTIC_IGNORE(-Wnested-externs)			\
		extern void  _func_entry(void);				\
		DIGNOSTIC_POP()						\
		_func_entry;						\
	})

/**
 * Micro-Architector definitions
 * Reference: https://developer.arm.com/docs/ddi0595/f/aarch64-system-registers/midr_el1
 */

#define CPU_IMPLEMENTER_RESERVE			0x00
#define CPU_IMPLEMENTER_ARM			0x41


#define CPU_PART_CORTEX_A57		0xD07
#define CPU_PART_CORTEX_A72		0xD08
#define CPU_PART_NEOVERSE_N1		0xD0C

#define MICRO_ARCH_ID(imp,part)	\
	(((CPU_IMPLEMENTER_##imp&0xff)<<24)|((CPU_PART_##part&0xfff)<<4))

#ifndef HWCAP_CPUID
#define HWCAP_CPUID (1<<11)
#endif

/**
 * @brief  get_micro_arch_id
 *
 * read micro-architector register instruction if possible.This function
 * provides microarchitecture information and make microarchitecture optimization
 * possible.
 *
 * Read system registers(MRS) is forbidden in userspace. If executed, it
 * will raise illegal instruction error. Kernel provides a solution for
 * this issue. The solution depends on HWCAP_CPUID flags. Reference(1)
 * describes how to use it. It provides a "illegal insstruction" handler
 * in kernel space, the handler will execute MRS and return the correct
 * value to userspace.
 *
 * To avoid too many kernel trap, this function MUST be only called in
 * dispatcher. And HWCAP must be match,That will make sure there are no
 * illegal instruction errors. HWCAP_CPUID should be available to get the
 * best performance.
 *
 * NOTICE:
 *     - HWCAP_CPUID should be available. Otherwise it returns reserve value
 *     - It MUST be called inside dispather.
 *     - It MUST meet the HWCAP requirements
 *
 * Example:
 *      DEFINE_INTERFACE_DISPATCHER(crc32_iscsi)
 *      {
 *              unsigned long auxval = getauxval(AT_HWCAP);
 *              // MUST do the judgement is MUST.
 *              if ((HWCAP_CRC32 | HWCAP_PMULL) == (auxval & (HWCAP_CRC32 | HWCAP_PMULL))) {
 *                      switch (get_micro_arch_id()) {
 *                      case MICRO_ARCH_ID(ARM, CORTEX_A57):
 *                              return PROVIDER_INFO(crc32_pmull_crc_for_a57);
 *                      case MICRO_ARCH_ID(ARM, CORTEX_A72):
 *                              return PROVIDER_INFO(crc32_pmull_crc_for_a72);
 *                      case MICRO_ARCH_ID(ARM, NEOVERSE_N1):
 *                              return PROVIDER_INFO(crc32_pmull_crc_for_n1);
 *                      case default:
 *                              return PROVIDER_INFO(crc32_pmull_crc_for_others);
 *                      }
 *              }
 *              return PROVIDER_BASIC(crc32_iscsi);
 *      }
 * KNOWN ISSUE:
 *   On a heterogeneous system (big.LITTLE), it will work but the performance
 *   might not be the best one as expected.
 *
 *   If this function is called on the big core, it will return the function
 *   optimized for the big core.
 *
 *   If execution is then scheduled to the little core. It will still work (1),
 *   but the function won't be optimized for the little core, thus the performance
 *   won't be as expected.
 *
 * References:
 * -  [CPU Feature detection](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/arm64/cpu-feature-registers.rst?h=v5.5)
 *
 */
static inline uint32_t get_micro_arch_id(void)
{
	uint64_t id=CPU_IMPLEMENTER_RESERVE;
#ifndef __APPLE__
	if ((getauxval(AT_HWCAP) & HWCAP_CPUID)) {
		/** Here will trap into kernel space */
		asm("mrs %0, MIDR_EL1 " : "=r" (id));
	}
#endif
	return id&0xff00fff0;
}



#endif /* __ASSEMBLY__ */
#endif