Mailing List Archive

commit a250debd2a76e4af058ad611657432f0626922e3
Author: Wei Chen <wei.chen@arm.com>
AuthorDate: Wed May 11 09:46:31 2022 +0800
Commit: Julien Grall <jgrall@amazon.com>
CommitDate: Mon May 16 18:10:31 2022 +0100

xen/arm: Print a 64-bit number in hex from early uart

Current putn function that is using for early print
only can print low 32-bit of AArch64 register. This
will lose some important messages while debugging
with early console. For example:
(XEN) Bringing up CPU5
- CPU 0000000100000100 booting -
Will be truncated to
(XEN) Bringing up CPU5
- CPU 00000100 booting -

In this patch, we increased the print loops and shift
bits to make putn print 64-bit number.

Signed-off-by: Wei Chen <wei.chen@arm.com>
Tested-by: Jiamei Xie <jiamei.xie@arm.com>
Acked-by: Julien Grall <jgrall@amazon.com>
---
xen/arch/arm/arm64/head.S | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
index 1fd35a8390..109ae7de0c 100644
--- a/xen/arch/arm/arm64/head.S
+++ b/xen/arch/arm/arm64/head.S
@@ -872,17 +872,19 @@ puts:
ret
ENDPROC(puts)

-/* Print a 32-bit number in hex. Specific to the PL011 UART.
+/*
+ * Print a 64-bit number in hex.
* x0: Number to print.
* x23: Early UART base address
- * Clobbers x0-x3 */
+ * Clobbers x0-x3
+ */
putn:
adr x1, hex
- mov x3, #8
+ mov x3, #16
1:
early_uart_ready x23, 2
- and x2, x0, #0xf0000000 /* Mask off the top nybble */
- lsr x2, x2, #28
+ and x2, x0, #(0xf<<60) /* Mask off the top nybble */
+ lsr x2, x2, #60
ldrb w2, [x1, x2] /* Convert to a char */
early_uart_transmit x23, w2
lsl x0, x0, #4 /* Roll it through one nybble at a time */
--
generated by git-patchbot for /home/xen/git/xen.git#master