limine: Add support for MAX_PAGING_MODE config option
diff --git a/CONFIG.md b/CONFIG.md
index 9a11da18..c4f22c23 100644
--- a/CONFIG.md
+++ b/CONFIG.md
@@ -123,6 +123,9 @@ Editor control options:
* `MODULE_CMDLINE` - A command line to be passed to a module. This key can also be specified multiple times. It applies to the module described by the last module key assigned.
* `RESOLUTION` - The resolution to be used. This setting takes the form of `<width>x<height>x<bpp>`. If the resolution is not available, Limine will pick another one automatically. Omitting `<bpp>` will default to 32.
* `KASLR` - For relocatable kernels, if set to `no`, disable kernel address space layout randomisation. KASLR is enabled by default.
+ * `MAX_PAGING_MODE` - Limit the maximum paging mode to one of the following:
+ - x86-64 and aarch64: `4level`, `5level`.
+ - riscv64: `sv39`, `sv48`, `sv57`.
* multiboot1 and multiboot2 protocols:
* `KERNEL_PATH` - The URI path of the kernel.
diff --git a/common/menu.c b/common/menu.c
index d42840c3..8edcc924 100644
--- a/common/menu.c
+++ b/common/menu.c
@@ -101,6 +101,7 @@ static const char *VALID_KEYS[] = {
"RESOLUTION",
"TEXTMODE",
"KASLR",
+ "MAX_PAGING_MODE",
"DRIVE",
"PARTITION",
"MBR_ID",
diff --git a/common/protos/limine.c b/common/protos/limine.c
index 755a18d0..fc53bbc1 100644
--- a/common/protos/limine.c
+++ b/common/protos/limine.c
@@ -440,22 +440,22 @@ noreturn void limine_load(char *config, char *cmdline) {
printv("limine: Requests count: %u\n", requests_count);
// Paging Mode
- int paging_mode, max_paging_mode;
+ int paging_mode, max_supported_paging_mode;
#if defined (__x86_64__) || defined (__i386__)
- paging_mode = max_paging_mode = PAGING_MODE_X86_64_4LVL;
+ paging_mode = max_supported_paging_mode = PAGING_MODE_X86_64_4LVL;
if (cpuid(0x00000007, 0, &eax, &ebx, &ecx, &edx) && (ecx & (1 << 16))) {
printv("limine: CPU has 5-level paging support\n");
- max_paging_mode = PAGING_MODE_X86_64_5LVL;
+ max_supported_paging_mode = PAGING_MODE_X86_64_5LVL;
}
#elif defined (__aarch64__)
- paging_mode = max_paging_mode = PAGING_MODE_AARCH64_4LVL;
+ paging_mode = max_supported_paging_mode = PAGING_MODE_AARCH64_4LVL;
// TODO(qookie): aarch64 also has optional 5 level paging when using 4K pages
#elif defined (__riscv64)
- max_paging_mode = vmm_max_paging_mode();
- paging_mode = max_paging_mode >= PAGING_MODE_RISCV_SV48 ? PAGING_MODE_RISCV_SV48 : PAGING_MODE_RISCV_SV39;
+ max_supported_paging_mode = vmm_max_paging_mode();
+ paging_mode = max_supported_paging_mode >= PAGING_MODE_RISCV_SV48 ? PAGING_MODE_RISCV_SV48 : PAGING_MODE_RISCV_SV39;
#else
#error Unknown architecture
@@ -475,14 +475,45 @@ FEAT_START
if (pm_request == NULL)
break;
- if (pm_request->mode > LIMINE_PAGING_MODE_MAX) {
- print("warning: ignoring invalid mode in paging mode request\n");
- break;
+ uint64_t paging_mode_max = LIMINE_PAGING_MODE_MAX;
+
+ char *max_paging_mode_s = config_get_value(config, 0, "MAX_PAGING_MODE");
+ if (max_paging_mode_s != NULL) {
+#if defined (__x86_64__) || defined (__i386__)
+ if (strcasecmp(max_paging_mode_s, "4level") == 0) {
+ paging_mode_max = LIMINE_PAGING_MODE_X86_64_4LVL;
+ } else if (strcasecmp(max_paging_mode_s, "5level") == 0) {
+ paging_mode_max = LIMINE_PAGING_MODE_X86_64_5LVL;
+ }
+#elif defined (__aarch64__)
+ if (strcasecmp(max_paging_mode_s, "4level") == 0) {
+ paging_mode_max = LIMINE_PAGING_MODE_AARCH64_4LVL;
+ } else if (strcasecmp(max_paging_mode_s, "5level") == 0) {
+ paging_mode_max = LIMINE_PAGING_MODE_AARCH64_5LVL;
+ }
+#elif defined (__riscv64)
+ if (strcasecmp(max_paging_mode_s, "sv39") == 0) {
+ paging_mode_max = LIMINE_PAGING_MODE_RISCV_SV39;
+ } else if (strcasecmp(max_paging_mode_s, "sv48") == 0) {
+ paging_mode_max = LIMINE_PAGING_MODE_RISCV_SV48;
+ } else if (strcasecmp(max_paging_mode_s, "sv57") == 0) {
+ paging_mode_max = LIMINE_PAGING_MODE_RISCV_SV57;
+ }
+#endif
+ else {
+ panic(true, "limine: Invalid MAX_PAGING_MODE: `%s`", max_paging_mode_s);
+ }
}
- paging_mode = paging_mode_limine_to_vmm(pm_request->mode);
- if (paging_mode > max_paging_mode)
- paging_mode = max_paging_mode;
+ uint64_t target_mode = pm_request->mode;
+ if (pm_request->mode > paging_mode_max) {
+ target_mode = paging_mode_max;
+ }
+
+ paging_mode = paging_mode_limine_to_vmm(target_mode);
+ if (paging_mode > max_supported_paging_mode) {
+ paging_mode = max_supported_paging_mode;
+ }
set_paging_mode(paging_mode, kaslr);
paging_mode_set = true;
diff --git a/test/limine.c b/test/limine.c
index d098a44c..a614d7bc 100644
--- a/test/limine.c
+++ b/test/limine.c
@@ -132,7 +132,7 @@ __attribute__((section(".limine_requests")))
static volatile struct limine_paging_mode_request _pm_request = {
.id = LIMINE_PAGING_MODE_REQUEST,
.revision = 0, .response = NULL,
- .mode = LIMINE_PAGING_MODE_DEFAULT,
+ .mode = LIMINE_PAGING_MODE_X86_64_5LVL,
.flags = 0,
};
