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qualcommax: add kernel cmdline replacement hack

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Add kernel command line replacement hack to qualcommax. Now we can
find and replace arguments in the kernel command line by setting
bootargs-find-1, bootargs-replace-1, bootargs-exact-match-1
and bootargs-find-2, bootargs-replace-2, bootargs-exact-match-2
under the chosen node in the device tree.

This hack replaces the first occurence of bootargs-find-X with
bootargs-replace-X. When bootargs-exact-match-X is set to "y",
then the replacement happens only if the kernel command line is
identical to bootargs-find-X.

Signed-off-by: Qiyuan Zhang <zhang.github@outlook.com>
This commit is contained in:
Qiyuan Zhang 2024-08-01 18:24:55 -04:00 committed by Paweł Owoc
parent 832ddc029d
commit c24e013668
1 changed files with 105 additions and 0 deletions
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105
target/linux/qualcommax/patches-6.6/0911-arm64-cmdline-replacement.patch Normal file
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@ -0,0 +1,105 @@
Subject: qualcommax: add kernel cmdline replacement hack
Add kernel command line replacement hack to qualcommax. Now we can
find and replace arguments in the kernel command line by setting
bootargs-find-1, bootargs-replace-1, bootargs-exact-match-1
and bootargs-find-2, bootargs-replace-2, bootargs-exact-match-2
under the chosen node in the device tree.
This hack replaces the first occurence of bootargs-find-X with
bootargs-replace-X. If bootargs-exact-match-X is set to "y",
then the replacement happens only if the kernel command line is
identical to bootargs-find-X.
Signed-off-by: Qiyuan Zhang <zhang.github@outlook.com>
---
drivers/of/fdt.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 71 insertions(+)
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1157,6 +1157,14 @@ int __init early_init_dt_scan_chosen(cha
const void *rng_seed;
const void *fdt = initial_boot_params;
+ int i, cmd_len, f_len, r_len, offset, step;
+ char *s_ptr, *l_end, *r_end, *cur_ptr, *end_ptr;
+ const char *exact_match;
+ const int bootargs_replace_num = 2;
+ const char *bootargs_replace_props[2][3] =
+ { {"bootargs-find-1", "bootargs-replace-1", "bootargs-exact-match-1"},
+ {"bootargs-find-2", "bootargs-replace-2", "bootargs-exact-match-2"} };
+
node = fdt_path_offset(fdt, "/chosen");
if (node < 0)
node = fdt_path_offset(fdt, "/chosen@0");
@@ -1185,6 +1193,69 @@ int __init early_init_dt_scan_chosen(cha
p = of_get_flat_dt_prop(node, "bootargs", &l);
if (p != NULL && l > 0)
strscpy(cmdline, p, min(l, COMMAND_LINE_SIZE));
+
+ for(i = 0; i < bootargs_replace_num; i++) {
+ p = of_get_flat_dt_prop(node, bootargs_replace_props[i][0], &f_len);
+
+ if (p == NULL || f_len == 0 )
+ continue;
+
+ exact_match = of_get_flat_dt_prop(node, bootargs_replace_props[i][2], &l);
+
+ if (exact_match != NULL && l > 0 && exact_match[0] == 'y') {
+ if(strncmp(cmdline, p, r_len) == 0)
+ s_ptr = cmdline;
+ else
+ s_ptr = NULL;
+ } else {
+ s_ptr = strstr(cmdline, p);
+ }
+
+ if(!s_ptr)
+ continue;
+
+ p = of_get_flat_dt_prop(node, bootargs_replace_props[i][1], &r_len);
+
+ if (p == NULL || r_len == 0)
+ continue;
+
+ pr_info("Input kernel commad line: %s\n", cmdline);
+
+ cmd_len = strlen(cmdline);
+
+ if (cmd_len - f_len + r_len < COMMAND_LINE_SIZE) {
+
+ pr_info("Replace kernel command line with %s\n", bootargs_replace_props[i][1]);
+
+ offset = r_len - f_len;
+
+ if (offset != 0) {
+ l_end = s_ptr + f_len - 1;
+ r_end = cmdline + cmd_len;
+
+ if (offset > 0) {
+ step = -1;
+ cur_ptr = r_end;
+ end_ptr = l_end + step;
+ } else {
+ step = 1;
+ cur_ptr = l_end;
+ end_ptr = r_end + step;
+ }
+
+ for (; cur_ptr != end_ptr; cur_ptr += step)
+ *(cur_ptr + offset) = *cur_ptr;
+ }
+
+ strncpy(s_ptr, p, r_len - 1);
+
+ pr_info("Kernel command line after replacement: %s\n", cmdline);
+ } else {
+ pr_err("Replace kernel command line with %s failed\n", bootargs_replace_props[i][1]);
+ }
+
+ }
+
p = of_get_flat_dt_prop(node, "bootargs-append", &l);
if (p != NULL && l > 0)
strlcat(cmdline, p, min_t(int, strlen(cmdline) + (int)l, COMMAND_LINE_SIZE));