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#include "pk.h"
#include "mmap.h"
#include "boot.h"
#include "elf.h"
#include "mtrap.h"
#include "frontend.h"
#include <stdbool.h>
elf_info current;
static void handle_option(const char* s)
{
switch (s[1])
{
case 's': // print cycle count upon termination
current.cycle0 = 1;
break;
case 'p': // disable demand paging
demand_paging = 0;
break;
default:
panic("unrecognized option: `%c'", s[1]);
break;
}
}
#define MAX_ARGS 64
typedef union {
uint64_t buf[MAX_ARGS];
char* argv[MAX_ARGS];
} arg_buf;
static size_t parse_args(arg_buf* args)
{
long r = frontend_syscall(SYS_getmainvars, va2pa(args), sizeof(*args), 0, 0, 0, 0, 0);
kassert(r == 0);
uint64_t* pk_argv = &args->buf[1];
// pk_argv[0] is the proxy kernel itself. skip it and any flags.
size_t pk_argc = args->buf[0], arg = 1;
for ( ; arg < pk_argc && *(char*)(uintptr_t)pk_argv[arg] == '-'; arg++)
handle_option((const char*)(uintptr_t)pk_argv[arg]);
for (size_t i = 0; arg + i < pk_argc; i++)
args->argv[i] = (char*)(uintptr_t)pk_argv[arg + i];
return pk_argc - arg;
}
static void init_tf(trapframe_t* tf, long pc, long sp)
{
memset(tf, 0, sizeof(*tf));
tf->status = (read_csr(sstatus) &~ SSTATUS_SPP &~ SSTATUS_SIE) | SSTATUS_SPIE;
tf->gpr[2] = sp;
tf->epc = pc;
}
static void run_loaded_program(size_t argc, char** argv, uintptr_t kstack_top)
{
// copy phdrs to user stack
size_t stack_top = current.stack_top - current.phdr_size;
memcpy((void*)stack_top, (void*)current.phdr, current.phdr_size);
current.phdr = stack_top;
// copy argv to user stack
for (size_t i = 0; i < argc; i++) {
size_t len = strlen((char*)(uintptr_t)argv[i])+1;
stack_top -= len;
memcpy((void*)stack_top, (void*)(uintptr_t)argv[i], len);
argv[i] = (void*)stack_top;
}
// copy envp to user stack
const char* envp[] = {
// environment goes here
};
size_t envc = sizeof(envp) / sizeof(envp[0]);
for (size_t i = 0; i < envc; i++) {
size_t len = strlen(envp[i]) + 1;
stack_top -= len;
memcpy((void*)stack_top, envp[i], len);
envp[i] = (void*)stack_top;
}
// align stack
stack_top &= -sizeof(void*);
struct {
long key;
long value;
} aux[] = {
{AT_ENTRY, current.entry},
{AT_PHNUM, current.phnum},
{AT_PHENT, current.phent},
{AT_PHDR, current.phdr},
{AT_PAGESZ, RISCV_PGSIZE},
{AT_SECURE, 0},
{AT_RANDOM, stack_top},
{AT_NULL, 0}
};
// place argc, argv, envp, auxp on stack
#define PUSH_ARG(type, value) do { \
*((type*)sp) = (type)value; \
sp += sizeof(type); \
} while (0)
#define STACK_INIT(type) do { \
unsigned naux = sizeof(aux)/sizeof(aux[0]); \
stack_top -= (1 + argc + 1 + envc + 1 + 2*naux) * sizeof(type); \
stack_top &= -16; \
long sp = stack_top; \
PUSH_ARG(type, argc); \
for (unsigned i = 0; i < argc; i++) \
PUSH_ARG(type, argv[i]); \
PUSH_ARG(type, 0); /* argv[argc] = NULL */ \
for (unsigned i = 0; i < envc; i++) \
PUSH_ARG(type, envp[i]); \
PUSH_ARG(type, 0); /* envp[envc] = NULL */ \
for (unsigned i = 0; i < naux; i++) { \
PUSH_ARG(type, aux[i].key); \
PUSH_ARG(type, aux[i].value); \
} \
} while (0)
STACK_INIT(uintptr_t);
if (current.cycle0) { // start timer if so requested
current.time0 = rdtime();
current.cycle0 = rdcycle();
current.instret0 = rdinstret();
}
trapframe_t tf;
init_tf(&tf, current.entry, stack_top);
__clear_cache(0, 0);
write_csr(sscratch, kstack_top);
start_user(&tf);
}
static void rest_of_boot_loader(uintptr_t kstack_top)
{
arg_buf args;
size_t argc = parse_args(&args);
if (!argc)
panic("tell me what ELF to load!");
// load program named by argv[0]
long phdrs[128];
current.phdr = (uintptr_t)phdrs;
current.phdr_size = sizeof(phdrs);
load_elf(args.argv[0], ¤t);
run_loaded_program(argc, args.argv, kstack_top);
}
void boot_loader()
{
extern char trap_entry;
write_csr(stvec, &trap_entry);
write_csr(sscratch, 0);
write_csr(sie, 0);
file_init();
enter_supervisor_mode(rest_of_boot_loader, pk_vm_init());
}
void boot_other_hart()
{
// stall all harts besides hart 0
while (1)
wfi();
}
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