diff options
Diffstat (limited to 'memdisk/setup.c')
| -rw-r--r-- | memdisk/setup.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/memdisk/setup.c b/memdisk/setup.c index 43151898..61cf420c 100644 --- a/memdisk/setup.c +++ b/memdisk/setup.c @@ -14,6 +14,8 @@ * ----------------------------------------------------------------------- */ #include <stdint.h> +#include <minmax.h> +#include <suffix_number.h> #include "bda.h" #include "dskprobe.h" #include "e820.h" @@ -705,6 +707,36 @@ static int stack_needed(void) return v; } +/* + * Set max memory by reservation + * Adds reservations to data in INT15h to prevent access to the top of RAM + * if there's any above the point specified. + */ +void setmaxmem(unsigned long long restop_ull) +{ + uint32_t restop; + struct e820range *ep; + const int int15restype = 2; + + /* insertrange() works on uint32_t */ + restop = min(restop_ull, UINT32_MAX); + /* printf(" setmaxmem '%08x%08x' => %08x\n", + (unsigned int)(restop_ull>>32), (unsigned int)restop_ull, restop); */ + + for (ep = ranges; ep->type != -1U; ep++) { + if (ep->type == 1) { /* Only if available */ + if (ep->start >= restop) { + /* printf(" %08x -> 2\n", ep->start); */ + ep->type = int15restype; + } else if (ep[1].start > restop) { + /* printf(" +%08x =2; cut %08x\n", restop, ep->start); */ + insertrange(restop, (ep[1].start - restop), int15restype); + } + } + } + parse_mem(); +} + struct real_mode_args rm_args; /* @@ -737,6 +769,7 @@ void setup(const struct real_mode_args *rm_args_ptr) int no_bpt; /* No valid BPT presented */ uint32_t boot_seg = 0; /* Meaning 0000:7C00 */ uint32_t boot_len = 512; /* One sector */ + const char *p; /* We need to copy the rm_args into their proper place */ memcpy(&rm_args, rm_args_ptr, sizeof rm_args); @@ -942,6 +975,10 @@ void setup(const struct real_mode_args *rm_args_ptr) pptr->cd_pkt.geom3 = (uint8_t)(pptr->heads); } + if ((p = getcmditem("mem")) != CMD_NOTFOUND) { + setmaxmem(suffix_number(p)); + } + /* The size is given by hptr->total_size plus the size of the E820 map -- 12 bytes per range; we may need as many as 2 additional ranges (each insertrange() can worst-case turn 1 area into 3) |