On 2023/4/7 20:03, Simon Horman wrote:
On Fri, Apr 07, 2023 at 06:02:05AM +0800, Chen Jiahao wrote:
On riscv, the current crash kernel allocation logic is trying to
allocate within 32bit addressible memory region by default, if
failed, try to allocate without 4G restriction.
In need of saving DMA zone memory while allocating a relatively large
crash kernel region, allocating the reserved memory top down in
high memory, without overlapping the DMA zone, is a mature solution.
Here introduce the parameter option crashkernel=X,[high,low].
One can reserve the crash kernel from high memory above DMA zone range
by explicitly passing "crashkernel=X,high"; or reserve a memory range
below 4G with "crashkernel=X,low".
Signed-off-by: Chen Jiahao <chenjiahao16@xxxxxxxxxx>
...
@@ -1180,14 +1206,37 @@ static void __init reserve_crashkernel(void)
return;
}
- ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
+ ret = parse_crashkernel(cmdline, memblock_phys_mem_size(),
&crash_size, &crash_base);
- if (ret || !crash_size)
+ if (ret == -ENOENT) {
+ /*
+ * crashkernel=X,[high,low] can be specified or not, but
+ * invalid value is not allowed.
nit: Perhaps something like this would be easier to correlate with the
code that follows:
/* Fallback to crashkernel=X,[high,low] */
Agreed, this would be more concise and accurate.
+ */
+ ret = parse_crashkernel_high(cmdline, 0, &crash_size, &crash_base);
+ if (ret || !crash_size)
+ return;
+
+ /*
+ * crashkernel=Y,low is valid only when crashkernel=X,high
+ * is passed and high memory is reserved successful.
nit: s/successful/successfully/
I will fix above nits and resend another version later, thanks.
+ */
+ ret = parse_crashkernel_low(cmdline, 0, &crash_low_size, &crash_base);
+ if (ret == -ENOENT)
+ crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
+ else if (ret)
+ return;
+
+ search_start = search_low_max;
+ } else if (ret || !crash_size) {
+ /* Invalid argument value specified */
return;
+ }
...
