From a8852f91967a7e55e62e30f5cc07d076092b8b78 Mon Sep 17 00:00:00 2001 From: Fabian Imhof Date: Sat, 5 Apr 2025 15:27:20 +0000 Subject: add wip context switch to user mode --- arch/x86_64/src/kernel/cpu/segment_register.cpp | 34 +++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 arch/x86_64/src/kernel/cpu/segment_register.cpp (limited to 'arch/x86_64/src/kernel/cpu/segment_register.cpp') diff --git a/arch/x86_64/src/kernel/cpu/segment_register.cpp b/arch/x86_64/src/kernel/cpu/segment_register.cpp new file mode 100644 index 0000000..f70c558 --- /dev/null +++ b/arch/x86_64/src/kernel/cpu/segment_register.cpp @@ -0,0 +1,34 @@ +#include "arch/kernel/cpu/segment_register.hpp" + +#include "arch/context_switching/interrupt_descriptor_table/segment_selector.hpp" + +namespace teachos::arch::kernel::cpu +{ + [[gnu::naked]] + auto reload_segment_registers() -> void + { + asm volatile("xor %rax, %rax\n" + "mov %rax, %ss\n" + "mov %rax, %ds\n" + "mov %rax, %es\n" + "mov %rax, %fs\n" + "mov %rax, %gs\n" + "ret"); + } + + [[gnu::naked]] + auto set_segment_registers(context_switching::interrupt_descriptor_table::segment_selector segment_selector) -> void + { + asm volatile("xor %%rax, %%rax\n" + "mov %[input], %%ax\n" + "mov %%rax, %%ss\n" + "mov %%rax, %%ds\n" + "mov %%rax, %%es\n" + "mov %%rax, %%fs\n" + "mov %%rax, %%gs\n" + "ret" + : /* No output from call */ + : [input] "m"(segment_selector)); + } + +} // namespace teachos::arch::kernel::cpu -- cgit v1.2.3 From 62d7fa83e831e84ea851d97b5c957146880ad69a Mon Sep 17 00:00:00 2001 From: Fabian Imhof Date: Thu, 10 Apr 2025 10:28:46 +0000 Subject: move context_switch function into cpp code --- arch/x86_64/src/kernel/cpu/segment_register.cpp | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/x86_64/src/kernel/cpu/segment_register.cpp') diff --git a/arch/x86_64/src/kernel/cpu/segment_register.cpp b/arch/x86_64/src/kernel/cpu/segment_register.cpp index f70c558..d7857dd 100644 --- a/arch/x86_64/src/kernel/cpu/segment_register.cpp +++ b/arch/x86_64/src/kernel/cpu/segment_register.cpp @@ -21,7 +21,6 @@ namespace teachos::arch::kernel::cpu { asm volatile("xor %%rax, %%rax\n" "mov %[input], %%ax\n" - "mov %%rax, %%ss\n" "mov %%rax, %%ds\n" "mov %%rax, %%es\n" "mov %%rax, %%fs\n" -- cgit v1.2.3 From dff78de795a89c181e9c94b26db2f16988e8f4d6 Mon Sep 17 00:00:00 2001 From: Fabian Imhof Date: Thu, 10 Apr 2025 12:11:55 +0000 Subject: move context_switch function and environment into different directory --- arch/x86_64/src/kernel/cpu/segment_register.cpp | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'arch/x86_64/src/kernel/cpu/segment_register.cpp') diff --git a/arch/x86_64/src/kernel/cpu/segment_register.cpp b/arch/x86_64/src/kernel/cpu/segment_register.cpp index d7857dd..9fb7433 100644 --- a/arch/x86_64/src/kernel/cpu/segment_register.cpp +++ b/arch/x86_64/src/kernel/cpu/segment_register.cpp @@ -30,4 +30,13 @@ namespace teachos::arch::kernel::cpu : [input] "m"(segment_selector)); } + auto read_code_segment_register() -> context_switching::interrupt_descriptor_table::segment_selector + { + context_switching::interrupt_descriptor_table::segment_selector current_value; + asm volatile("mov %%cs, %[output]" : [output] "=r"(current_value)); + return current_value; + } + + auto validate_segment_registers() -> context_switching::interrupt_descriptor_table::segment_selector {} + } // namespace teachos::arch::kernel::cpu -- cgit v1.2.3 From 87091e2246d2c4c794d9d6a0c5398ca80d92335a Mon Sep 17 00:00:00 2001 From: Fabian Imhof Date: Thu, 10 Apr 2025 12:29:19 +0000 Subject: add register validation and asserts --- arch/x86_64/src/kernel/cpu/segment_register.cpp | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) (limited to 'arch/x86_64/src/kernel/cpu/segment_register.cpp') diff --git a/arch/x86_64/src/kernel/cpu/segment_register.cpp b/arch/x86_64/src/kernel/cpu/segment_register.cpp index 9fb7433..cb367b6 100644 --- a/arch/x86_64/src/kernel/cpu/segment_register.cpp +++ b/arch/x86_64/src/kernel/cpu/segment_register.cpp @@ -1,6 +1,7 @@ #include "arch/kernel/cpu/segment_register.hpp" #include "arch/context_switching/interrupt_descriptor_table/segment_selector.hpp" +#include "arch/exception_handling/assert.hpp" namespace teachos::arch::kernel::cpu { @@ -37,6 +38,26 @@ namespace teachos::arch::kernel::cpu return current_value; } - auto validate_segment_registers() -> context_switching::interrupt_descriptor_table::segment_selector {} + auto validate_data_segment_registers() -> context_switching::interrupt_descriptor_table::segment_selector + { + context_switching::interrupt_descriptor_table::segment_selector ss; + context_switching::interrupt_descriptor_table::segment_selector ds; + context_switching::interrupt_descriptor_table::segment_selector es; + context_switching::interrupt_descriptor_table::segment_selector fs; + context_switching::interrupt_descriptor_table::segment_selector gs; + + asm volatile( + "mov %%ss, %[ss_output]\n" + "mov %%ds, %[ds_output]\n" + "mov %%es, %[es_output]\n" + "mov %%fs, %[fs_output]\n" + "mov %%gs, %[gs_output]\n" + : [ss_output] "=r"(ss), [ds_output] "=r"(ds), [es_output] "=r"(es), [fs_output] "=r"(fs), [gs_output] "=r"(gs)); + + auto result = ss == ds && ss == es && ss == fs && ss == gs; + exception_handling::assert(result, "[Segment Register] Values in data register are not the same."); + + return ss; + } } // namespace teachos::arch::kernel::cpu -- cgit v1.2.3 From 9a185c1533bd2197d0e830369b4cc26abf88e2c9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Matteo=20Gm=C3=BCr?= Date: Fri, 11 Apr 2025 09:25:04 +0000 Subject: Document methods and move them into kernel cpu folder --- arch/x86_64/src/kernel/cpu/segment_register.cpp | 48 ++++++++++++++++++++++--- 1 file changed, 43 insertions(+), 5 deletions(-) (limited to 'arch/x86_64/src/kernel/cpu/segment_register.cpp') diff --git a/arch/x86_64/src/kernel/cpu/segment_register.cpp b/arch/x86_64/src/kernel/cpu/segment_register.cpp index cb367b6..44b4eff 100644 --- a/arch/x86_64/src/kernel/cpu/segment_register.cpp +++ b/arch/x86_64/src/kernel/cpu/segment_register.cpp @@ -6,7 +6,7 @@ namespace teachos::arch::kernel::cpu { [[gnu::naked]] - auto reload_segment_registers() -> void + auto reload_data_segment_registers() -> void { asm volatile("xor %rax, %rax\n" "mov %rax, %ss\n" @@ -18,7 +18,8 @@ namespace teachos::arch::kernel::cpu } [[gnu::naked]] - auto set_segment_registers(context_switching::interrupt_descriptor_table::segment_selector segment_selector) -> void + auto set_data_segment_registers(context_switching::interrupt_descriptor_table::segment_selector segment_selector) + -> void { asm volatile("xor %%rax, %%rax\n" "mov %[input], %%ax\n" @@ -38,7 +39,8 @@ namespace teachos::arch::kernel::cpu return current_value; } - auto validate_data_segment_registers() -> context_switching::interrupt_descriptor_table::segment_selector + auto validate_data_segment_registers(context_switching::interrupt_descriptor_table::segment_selector data_segment) + -> void { context_switching::interrupt_descriptor_table::segment_selector ss; context_switching::interrupt_descriptor_table::segment_selector ds; @@ -54,10 +56,46 @@ namespace teachos::arch::kernel::cpu "mov %%gs, %[gs_output]\n" : [ss_output] "=r"(ss), [ds_output] "=r"(ds), [es_output] "=r"(es), [fs_output] "=r"(fs), [gs_output] "=r"(gs)); - auto result = ss == ds && ss == es && ss == fs && ss == gs; + auto result = (ss == ds && ss == es && ss == fs && ss == gs); exception_handling::assert(result, "[Segment Register] Values in data register are not the same."); + result = (ss == data_segment); + exception_handling::assert( + result, "[Segment Register] Expected Data Segment is not the same as the value in the Stack Segment register."); + } + + auto validate_code_segment_register(context_switching::interrupt_descriptor_table::segment_selector code_segment) + -> void + { + auto const cs = read_code_segment_register(); + exception_handling::assert( + cs == code_segment, + "[Segment Register] Expected Code Segment is not the same as the value in the Code Segment register."); + } + + auto validate_segment_registers(context_switching::interrupt_descriptor_table::segment_selector data_segment, + context_switching::interrupt_descriptor_table::segment_selector code_segment) -> void + { + validate_data_segment_registers(data_segment); + validate_code_segment_register(code_segment); + } + + [[gnu::naked]] + auto set_code_segment_register(context_switching::interrupt_descriptor_table::segment_selector data_segment, + context_switching::interrupt_descriptor_table::segment_selector code_segment, + uint64_t address) -> void + { + asm volatile("mov %%rsp, %%rax\n" + "push %[data_segment]\n" + "push %%rax\n" + "pushfq\n" + "push %[code_segment]\n" + "mov %[return_function], %%rax\n" + "push %%rax\n" - return ss; + "iretq\n" + : + : [data_segment] "m"(data_segment), [code_segment] "m"(code_segment), [return_function] "r"(address) + : "rax"); } } // namespace teachos::arch::kernel::cpu -- cgit v1.2.3 From 3c7250a32033700944ed6f3d2174756245b22e83 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Matteo=20Gm=C3=BCr?= Date: Fri, 11 Apr 2025 13:37:55 +0000 Subject: Adjust variable name --- arch/x86_64/src/kernel/cpu/segment_register.cpp | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'arch/x86_64/src/kernel/cpu/segment_register.cpp') diff --git a/arch/x86_64/src/kernel/cpu/segment_register.cpp b/arch/x86_64/src/kernel/cpu/segment_register.cpp index 44b4eff..891d72c 100644 --- a/arch/x86_64/src/kernel/cpu/segment_register.cpp +++ b/arch/x86_64/src/kernel/cpu/segment_register.cpp @@ -18,8 +18,7 @@ namespace teachos::arch::kernel::cpu } [[gnu::naked]] - auto set_data_segment_registers(context_switching::interrupt_descriptor_table::segment_selector segment_selector) - -> void + auto set_data_segment_registers(context_switching::interrupt_descriptor_table::segment_selector data_segment) -> void { asm volatile("xor %%rax, %%rax\n" "mov %[input], %%ax\n" @@ -29,7 +28,7 @@ namespace teachos::arch::kernel::cpu "mov %%rax, %%gs\n" "ret" : /* No output from call */ - : [input] "m"(segment_selector)); + : [input] "m"(data_segment)); } auto read_code_segment_register() -> context_switching::interrupt_descriptor_table::segment_selector -- cgit v1.2.3 From e5c62b114da77d278afe077b222b2f4feae2b94e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Matteo=20Gm=C3=BCr?= Date: Fri, 11 Apr 2025 14:01:44 +0000 Subject: Add rax clobbered register to all segment register write calls --- arch/x86_64/src/kernel/cpu/segment_register.cpp | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'arch/x86_64/src/kernel/cpu/segment_register.cpp') diff --git a/arch/x86_64/src/kernel/cpu/segment_register.cpp b/arch/x86_64/src/kernel/cpu/segment_register.cpp index 891d72c..9933e92 100644 --- a/arch/x86_64/src/kernel/cpu/segment_register.cpp +++ b/arch/x86_64/src/kernel/cpu/segment_register.cpp @@ -14,7 +14,10 @@ namespace teachos::arch::kernel::cpu "mov %rax, %es\n" "mov %rax, %fs\n" "mov %rax, %gs\n" - "ret"); + "ret" + : /* No output from call */ + : /* No input to call */ + : "rax"); } [[gnu::naked]] @@ -28,7 +31,8 @@ namespace teachos::arch::kernel::cpu "mov %%rax, %%gs\n" "ret" : /* No output from call */ - : [input] "m"(data_segment)); + : [input] "m"(data_segment) + : "rax"); } auto read_code_segment_register() -> context_switching::interrupt_descriptor_table::segment_selector @@ -90,7 +94,6 @@ namespace teachos::arch::kernel::cpu "push %[code_segment]\n" "mov %[return_function], %%rax\n" "push %%rax\n" - "iretq\n" : : [data_segment] "m"(data_segment), [code_segment] "m"(code_segment), [return_function] "r"(address) -- cgit v1.2.3 From 4909c80b31f3198030d3e666db87cfd39ac87c6f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Matteo=20Gm=C3=BCr?= Date: Fri, 11 Apr 2025 14:07:29 +0000 Subject: Remove gnu::naked functions where not necessary. --- arch/x86_64/src/kernel/cpu/segment_register.cpp | 36 +++++++++++-------------- 1 file changed, 16 insertions(+), 20 deletions(-) (limited to 'arch/x86_64/src/kernel/cpu/segment_register.cpp') diff --git a/arch/x86_64/src/kernel/cpu/segment_register.cpp b/arch/x86_64/src/kernel/cpu/segment_register.cpp index 9933e92..b59cd1b 100644 --- a/arch/x86_64/src/kernel/cpu/segment_register.cpp +++ b/arch/x86_64/src/kernel/cpu/segment_register.cpp @@ -5,22 +5,19 @@ namespace teachos::arch::kernel::cpu { - [[gnu::naked]] auto reload_data_segment_registers() -> void { - asm volatile("xor %rax, %rax\n" - "mov %rax, %ss\n" - "mov %rax, %ds\n" - "mov %rax, %es\n" - "mov %rax, %fs\n" - "mov %rax, %gs\n" - "ret" - : /* No output from call */ - : /* No input to call */ + asm volatile("xor %%rax, %%rax\n" + "mov %%rax, %%ss\n" + "mov %%rax, %%ds\n" + "mov %%rax, %%es\n" + "mov %%rax, %%fs\n" + "mov %%rax, %%gs\n" + : /* no output from call */ + : /* no input to call */ : "rax"); } - [[gnu::naked]] auto set_data_segment_registers(context_switching::interrupt_descriptor_table::segment_selector data_segment) -> void { asm volatile("xor %%rax, %%rax\n" @@ -29,15 +26,14 @@ namespace teachos::arch::kernel::cpu "mov %%rax, %%es\n" "mov %%rax, %%fs\n" "mov %%rax, %%gs\n" - "ret" - : /* No output from call */ + : /* no output from call */ : [input] "m"(data_segment) : "rax"); } auto read_code_segment_register() -> context_switching::interrupt_descriptor_table::segment_selector { - context_switching::interrupt_descriptor_table::segment_selector current_value; + context_switching::interrupt_descriptor_table::segment_selector current_value{}; asm volatile("mov %%cs, %[output]" : [output] "=r"(current_value)); return current_value; } @@ -45,11 +41,11 @@ namespace teachos::arch::kernel::cpu auto validate_data_segment_registers(context_switching::interrupt_descriptor_table::segment_selector data_segment) -> void { - context_switching::interrupt_descriptor_table::segment_selector ss; - context_switching::interrupt_descriptor_table::segment_selector ds; - context_switching::interrupt_descriptor_table::segment_selector es; - context_switching::interrupt_descriptor_table::segment_selector fs; - context_switching::interrupt_descriptor_table::segment_selector gs; + context_switching::interrupt_descriptor_table::segment_selector ss{}; + context_switching::interrupt_descriptor_table::segment_selector ds{}; + context_switching::interrupt_descriptor_table::segment_selector es{}; + context_switching::interrupt_descriptor_table::segment_selector fs{}; + context_switching::interrupt_descriptor_table::segment_selector gs{}; asm volatile( "mov %%ss, %[ss_output]\n" @@ -95,7 +91,7 @@ namespace teachos::arch::kernel::cpu "mov %[return_function], %%rax\n" "push %%rax\n" "iretq\n" - : + : /* no output from call */ : [data_segment] "m"(data_segment), [code_segment] "m"(code_segment), [return_function] "r"(address) : "rax"); } -- cgit v1.2.3 From 187eba4eca3ea46d8c26419168e525242338dae4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Matteo=20Gm=C3=BCr?= Date: Sun, 27 Apr 2025 13:18:49 +0000 Subject: Simplify syscall setup --- arch/x86_64/src/kernel/cpu/segment_register.cpp | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/x86_64/src/kernel/cpu/segment_register.cpp') diff --git a/arch/x86_64/src/kernel/cpu/segment_register.cpp b/arch/x86_64/src/kernel/cpu/segment_register.cpp index b59cd1b..b08c9c4 100644 --- a/arch/x86_64/src/kernel/cpu/segment_register.cpp +++ b/arch/x86_64/src/kernel/cpu/segment_register.cpp @@ -78,7 +78,6 @@ namespace teachos::arch::kernel::cpu validate_code_segment_register(code_segment); } - [[gnu::naked]] auto set_code_segment_register(context_switching::interrupt_descriptor_table::segment_selector data_segment, context_switching::interrupt_descriptor_table::segment_selector code_segment, uint64_t address) -> void -- cgit v1.2.3