[x86 setup] edd.c: make sure MBR signatures actually get reported

When filling in the MBR signature array, the setup code failed to advance
boot_params.edd_mbr_sig_buf_entries, which resulted in the valid data
being ignored.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

diff --git a/arch/i386/boot/edd.c b/arch/i386/boot/edd.c
index d65dd21..82b5c84 100644 (file)
--- a/arch/i386/boot/edd.c
+++ b/arch/i386/boot/edd.c
@@ -37,11 +37,10 @@ static int read_mbr(u8 devno, void *buf)
        return -(u8)ax;         /* 0 or -1 */
 }
 
-static u32 read_mbr_sig(u8 devno, struct edd_info *ei)
+static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig)
 {
        int sector_size;
        char *mbrbuf_ptr, *mbrbuf_end;
-       u32 mbrsig;
        u32 buf_base, mbr_base;
        extern char _end[];
 
@@ -57,15 +56,15 @@ static u32 read_mbr_sig(u8 devno, struct edd_info *ei)
 
        /* Make sure we actually have space on the heap... */
        if (!(boot_params.hdr.loadflags & CAN_USE_HEAP))
-               return 0;
+               return -1;
        if (mbrbuf_end > (char *)(size_t)boot_params.hdr.heap_end_ptr)
-               return 0;
+               return -1;
 
        if (read_mbr(devno, mbrbuf_ptr))
-               return 0;
+               return -1;
 
-       mbrsig = *(u32 *)&mbrbuf_ptr[EDD_MBR_SIG_OFFSET];
-       return mbrsig;
+       *mbrsig = *(u32 *)&mbrbuf_ptr[EDD_MBR_SIG_OFFSET];
+       return 0;
 }
 
 static int get_edd_info(u8 devno, struct edd_info *ei)
@@ -132,6 +131,7 @@ void query_edd(void)
        int do_edd = 1;
        int devno;
        struct edd_info ei, *edp;
+       u32 *mbrptr;
 
        if (cmdline_find_option("edd", eddarg, sizeof eddarg) > 0) {
                if (!strcmp(eddarg, "skipmbr") || !strcmp(eddarg, "skip"))
@@ -140,7 +140,8 @@ void query_edd(void)
                        do_edd = 0;
        }
 
-       edp = (struct edd_info *)boot_params.eddbuf;
+       edp    = boot_params.eddbuf;
+       mbrptr = boot_params.edd_mbr_sig_buffer;
 
        if (!do_edd)
                return;
@@ -158,11 +159,8 @@ void query_edd(void)
                        boot_params.eddbuf_entries++;
                }
 
-               if (do_mbr) {
-                       u32 mbr_sig;
-                       mbr_sig = read_mbr_sig(devno, &ei);
-                       boot_params.edd_mbr_sig_buffer[devno-0x80] = mbr_sig;
-               }
+               if (do_mbr && !read_mbr_sig(devno, &ei, mbrptr++))
+                       boot_params.edd_mbr_sig_buf_entries = devno-0x80+1;
        }
 }