[SLOF] [PATCH v2] boot: do not use catpad to concatenate strings

[Nikunj A Dadhania]

The catpad size is 1K size, which can be hit easily hit with around 20 devices
with bootindex.

Open code EVALUATE such that concatenation is not required. Replace usage of
$cat with a 16K buffer allocated here.

Reported here: https://github.com/qemu/SLOF/issues/3

Signed-off-by: Nikunj A Dadhania <nikunj at linux.vnet.ibm.com>

---

qemu-system-ppc64 -nographic -nodefaults -serial stdio -monitor pty -m 2G \
-device virtio-scsi-pci    \
`for ((i=2;i<=50;i++)) ; \
do echo -n "  -drive file=/tmp/storage$i.qcow2,if=none,id=drive$i,format=qcow2 \
-device
scsi-hd,drive=drive$i,id=disk$i,channel=0,scsi-id=0,lun=$i,bootindex=$i"; \
done;` \
-drive file=guest.disk,if=none,id=drv1,format=qcow2,cache=none \
-device scsi-hd,drive=drv1,bootindex=1 -boot menu=on,splash-time=3000,strict=on
---
 slof/fs/boot.fs | 30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/slof/fs/boot.fs b/slof/fs/boot.fs
index 1fd7439..8a30195 100644
--- a/slof/fs/boot.fs
+++ b/slof/fs/boot.fs
@@ -15,6 +15,9 @@
 VARIABLE state-valid false state-valid !
 CREATE go-args 2 cells allot go-args 2 cells erase
 
+4000 CONSTANT BOOT_DEV_SIZE
+CREATE bootdev-buf BOOT_DEV_SIZE allot
+
 \ \\\\\\\\\\\\\\ Structure/Implementation Dependent Methods
 
 : $bootargs
@@ -24,13 +27,17 @@ CREATE go-args 2 cells allot go-args 2 cells erase
 ;
 
 : $bootdev ( -- device-name len )
-   bootdevice 2@ dup IF s"  " $cat THEN
+   bootdev-buf BOOT_DEV_SIZE erase
+   bootdevice 2@ dup IF
+      swap bootdev-buf 2 pick move
+      bootdev-buf swap s"  " string-cat
+   THEN
    s" diagnostic-mode?" evaluate IF
       s" diag-device" evaluate
    ELSE
       s" boot-device" evaluate
    THEN
-   $cat \ prepend bootdevice setting from vpd-bootlist
+   string-cat \ concatenate both
    strdup
    ?dup 0= IF
       disable-watchdog
@@ -51,7 +58,12 @@ CREATE go-args 2 cells allot go-args 2 cells erase
 ' (set-boot-device) to set-boot-device
 
 : (add-boot-device) ( str len -- )	\ Concatenate " str" to "bootdevice"
-   bootdevice 2@ ?dup IF $cat-space ELSE drop THEN set-boot-device
+   bootdevice 2@ ?dup IF
+      swap bootdev-buf 2 pick move
+      bootdev-buf swap s"  " string-cat
+      2swap string-cat
+   ELSE drop THEN
+   set-boot-device
 ;
 
 ' (add-boot-device) to add-boot-device
@@ -221,11 +233,19 @@ defer go ( -- )
    ELSE
       drop
    THEN
-   set-boot-args s" parse-load " $bootdev $cat strdup evaluate
+   set-boot-args
+   save-source  -1 to source-id
+   $bootdev dup #ib ! span ! to ib
+   0 >in !
+   ['] parse-load catch restore-source throw
 ;
 
 : load-next ( -- success )	\ Continue after go failed
-   load-list 2@ ?dup IF s" parse-load " 2swap $cat strdup evaluate
+   load-list 2@ ?dup IF
+      save-source  -1 to source-id
+      dup #ib ! span ! to ib
+      0 >in !
+      ['] parse-load catch restore-source throw
    ELSE drop false THEN
 ;
 
-- 
2.13.6