From: Alan Cox <alan@linux.intel.com>
Date: Sun, 25 Jan 2015 00:24:06 +0000 (+0000)
Subject: execve: use direct user mappings
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=62725839c8ea568f7af3259079b125cfc09fe372;p=FUZIX.git

execve: use direct user mappings

If your disk devices don't support this then you'll need to enable the
CONFIG_LEGACY_EXEC option and fix the target. (This probably will get renamed
because if we get to stuff like 68000 it may be we have a cache big enough to
make execve via it useful)

This makes execve much faster, way faster on slow memory devices. The remaining
performance killer is the lack of vfork.
---

diff --git a/Kernel/syscall_exec.c b/Kernel/syscall_exec.c
index 3b325725..66580314 100644
--- a/Kernel/syscall_exec.c
+++ b/Kernel/syscall_exec.c
@@ -13,6 +13,7 @@ static int bload(inoptr i, uint16_t bl, uint16_t base, uint16_t len)
 		if (blk == NULLBLK)
 			uzero((uint8_t *)base, 512);
 		else {
+#ifdef CONFIG_LEGACY_EXEC
 			buf = bread(i->c_dev, blk, 0);
 			if (buf == NULL) {
 				kprintf("bload failed.\n");
@@ -21,6 +22,17 @@ static int bload(inoptr i, uint16_t bl, uint16_t base, uint16_t len)
 			uput(buf, (uint8_t *)base, cp);
 			bufdiscard((bufptr)buf);
 			brelse((bufptr)buf);
+#else
+			/* Might be worth spotting sequential blocks and
+			   merging ? */
+			udata.u_offset = blk << 9;
+			udata.u_count = 512;
+			udata.u_base = (uint8_t *)base;
+			if (cdread(i->c_dev, 0) < 0) {
+				kprintf("bload failed.\n");
+				return -1;
+			}
+#endif
 		}
 		base += cp;
 		len -= cp;