Remove stack pointer for each process

Since 6132623dbf30 ("Share the same stack everywhere") the same stack is
used everywhere. Hence, it's rather pointless for each task to have a
pointer to a stack which is the same and that is never read.

Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>

3 files changed, 16 insertions, 23 deletions

diff --git a/include/fbos/sched.h b/include/fbos/sched.h
index 67778da..ced620c 100644
--- a/include/fbos/sched.h
+++ b/include/fbos/sched.h
@@ -17,12 +17,6 @@ enum task_id {
 
 // All the information we need to grab for processes.
 struct task_struct {
-	// The stack allocated for the process. As you can see when initializing
-	// each process on `kernel/main.c`, we go over the top for its size. There
-	// is also the fact that we need to keep this as the first attribue to allow
-	// for simple `sp` values.
-	void *stack;
-
 	// Name of the task to be printed for debugging purposes.
 	const char name[TASK_NAME_LEN];
 
diff --git a/kernel/main.c b/kernel/main.c
index 5a11816..a2e4d13 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -5,22 +5,23 @@
 #include <fbos/string.h>
 #include <fbos/dt.h>
 
-// Stack to be used by our processes. "Blasphemy!" I hear you say. "How dare you
-// use the same stack for kernel and user space?" It's not like this is some
-// sort of utopian system in which everyone shares everything, but since this
-// stupidly simple kernel does not even bother to implement paging nor any other
-// memory protection of any kind, it's not like separating stacks for each
-// process and kernel space would make much of a difference. Hence, let's keep
-// it simple and have the same stack everwhere.
+// Stack to be used by our processes, which is initialized in head.S.
+// "Blasphemy!" I hear you say. "How dare you use the same stack for kernel and
+// user space?" It's not like this is some sort of utopian system in which
+// everyone shares everything, but since this stupidly simple kernel does not
+// even bother to implement paging nor any other memory protection of any kind,
+// it's not like separating stacks for each process and kernel space would make
+// much of a difference. Hence, let's keep it simple and have the same stack
+// everwhere.
 uint64_t stack[STACK_SIZE / sizeof(uint64_t)];
 
 // Initialize the list of structs by providing a fixed stack address and empty
 // values everywhere else.
 struct task_struct tasks[4] = {
-	[TASK_INIT] = { .stack = stack, .name = "init", .entry_addr = nullptr, },
-	[TASK_FIZZ] = { .stack = stack, .name = "fizz", .entry_addr = nullptr, },
-	[TASK_BUZZ] = { .stack = stack, .name = "buzz", .entry_addr = nullptr, },
-	[TASK_FIZZBUZZ] = { .stack = stack, .name = "fizzbuzz", .entry_addr = nullptr, },
+	[TASK_INIT] = { .name = "init", .entry_addr = nullptr, },
+	[TASK_FIZZ] = { .name = "fizz", .entry_addr = nullptr, },
+	[TASK_BUZZ] = { .name = "buzz", .entry_addr = nullptr, },
+	[TASK_FIZZBUZZ] = { .name = "fizzbuzz", .entry_addr = nullptr, },
 };
 
 // Defined in fbos/init.h.
diff --git a/test/test_initrd.c b/test/test_initrd.c
index fb5197b..75611a7 100644
--- a/test/test_initrd.c
+++ b/test/test_initrd.c
@@ -6,13 +6,11 @@
 #include <fbos/sched.h>
 #include <fbos/mm.h>
 
-unsigned long stack[STACK_SIZE / sizeof(unsigned long)];
-
 struct task_struct tasks[4] = {
-	[TASK_INIT] = { .stack = stack, .entry_addr = NULL, },
-	[TASK_FIZZ] = { .stack = stack, .entry_addr = NULL, },
-	[TASK_BUZZ] = { .stack = stack, .entry_addr = NULL, },
-	[TASK_FIZZBUZZ] = { .stack = stack, .entry_addr = NULL, },
+	[TASK_INIT] = { .entry_addr = NULL, },
+	[TASK_FIZZ] = { .entry_addr = NULL, },
+	[TASK_BUZZ] = { .entry_addr = NULL, },
+	[TASK_FIZZBUZZ] = { .entry_addr = NULL, },
 };
 
 int main(void)