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tool headers nolibc: add RISCV support
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This adds support for the RISCV architecture (32 and 64 bit) to the
nolibc header file.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
[willy: minimal rewording of the commit message]
Signed-off-by: Willy Tarreau <w@1wt.eu>
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Pranith Kumar authored and Willy Tarreau committed May 8, 2019
1 parent 80f2321 commit 582e84f
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194 changes: 194 additions & 0 deletions tools/include/nolibc/nolibc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1243,6 +1243,200 @@ struct sys_stat_struct {
long st_pad4[14];
};

#elif defined(__riscv)

#if __riscv_xlen == 64
#define PTRLOG "3"
#define SZREG "8"
#elif __riscv_xlen == 32
#define PTRLOG "2"
#define SZREG "4"
#endif

/* Syscalls for RISCV :
* - stack is 16-byte aligned
* - syscall number is passed in a7
* - arguments are in a0, a1, a2, a3, a4, a5
* - the system call is performed by calling ecall
* - syscall return comes in a0
* - the arguments are cast to long and assigned into the target
* registers which are then simply passed as registers to the asm code,
* so that we don't have to experience issues with register constraints.
*/

#define my_syscall0(num) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0"); \
\
asm volatile ( \
"ecall\n\t" \
: "=r"(_arg1) \
: "r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})

#define my_syscall1(num, arg1) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
\
asm volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})

#define my_syscall2(num, arg1, arg2) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
\
asm volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_arg2), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})

#define my_syscall3(num, arg1, arg2, arg3) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
register long _arg3 asm("a2") = (long)(arg3); \
\
asm volatile ( \
"ecall\n\t" \
: "+r"(_arg1) \
: "r"(_arg2), "r"(_arg3), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})

#define my_syscall4(num, arg1, arg2, arg3, arg4) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
register long _arg3 asm("a2") = (long)(arg3); \
register long _arg4 asm("a3") = (long)(arg4); \
\
asm volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_arg2), "r"(_arg3), "r"(_arg4), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})

#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
register long _arg3 asm("a2") = (long)(arg3); \
register long _arg4 asm("a3") = (long)(arg4); \
register long _arg5 asm("a4") = (long)(arg5); \
\
asm volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})

#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \
({ \
register long _num asm("a7") = (num); \
register long _arg1 asm("a0") = (long)(arg1); \
register long _arg2 asm("a1") = (long)(arg2); \
register long _arg3 asm("a2") = (long)(arg3); \
register long _arg4 asm("a3") = (long)(arg4); \
register long _arg5 asm("a4") = (long)(arg5); \
register long _arg6 asm("a5") = (long)(arg6); \
\
asm volatile ( \
"ecall\n" \
: "+r"(_arg1) \
: "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), "r"(_arg6), \
"r"(_num) \
: "memory", "cc" \
); \
_arg1; \
})

/* startup code */
asm(".section .text\n"
".global _start\n"
"_start:\n"
".option push\n"
".option norelax\n"
"lla gp, __global_pointer$\n"
".option pop\n"
"ld a0, 0(sp)\n" // argc (a0) was in the stack
"add a1, sp, "SZREG"\n" // argv (a1) = sp
"slli a2, a0, "PTRLOG"\n" // envp (a2) = SZREG*argc ...
"add a2, a2, "SZREG"\n" // + SZREG (skip null)
"add a2,a2,a1\n" // + argv
"andi sp,a1,-16\n" // sp must be 16-byte aligned
"call main\n" // main() returns the status code, we'll exit with it.
"andi a0, a0, 0xff\n" // limit exit code to 8 bits
"li a7, 93\n" // NR_exit == 93
"ecall\n"
"");

/* fcntl / open */
#define O_RDONLY 0
#define O_WRONLY 1
#define O_RDWR 2
#define O_CREAT 0x100
#define O_EXCL 0x200
#define O_NOCTTY 0x400
#define O_TRUNC 0x1000
#define O_APPEND 0x2000
#define O_NONBLOCK 0x4000
#define O_DIRECTORY 0x200000

struct sys_stat_struct {
unsigned long st_dev; /* Device. */
unsigned long st_ino; /* File serial number. */
unsigned int st_mode; /* File mode. */
unsigned int st_nlink; /* Link count. */
unsigned int st_uid; /* User ID of the file's owner. */
unsigned int st_gid; /* Group ID of the file's group. */
unsigned long st_rdev; /* Device number, if device. */
unsigned long __pad1;
long st_size; /* Size of file, in bytes. */
int st_blksize; /* Optimal block size for I/O. */
int __pad2;
long st_blocks; /* Number 512-byte blocks allocated. */
long st_atime; /* Time of last access. */
unsigned long st_atime_nsec;
long st_mtime; /* Time of last modification. */
unsigned long st_mtime_nsec;
long st_ctime; /* Time of last status change. */
unsigned long st_ctime_nsec;
unsigned int __unused4;
unsigned int __unused5;
};

#endif


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